Move container_registry user docs to new location

## What does this MR do?

Move container_registry user docs to new location and refactor them a bit.

Part of https://gitlab.com/gitlab-org/gitlab-ce/issues/3349

## Moving docs to a new location?

See the guidelines: http://docs.gitlab.com/ce/development/doc_styleguide.html#changing-document-location

- [ ] Make sure the old link is not removed and has its contents replaced with a link to the new location.
- [ ] Make sure internal links pointing to the document in question are not broken.
- [ ] Search and replace any links referring to old docs in GitLab Rails app, specifically under the `app/views/` directory.
- [ ] If working on CE, submit an MR to EE with the changes as well.

See merge request !6516

Replace bootstrap caret with fontawesome caret

## What does this MR do?

1. Replaces all occurrences of `.caret` with fontawesome's caret (`fa-caret-down` for most cases)
2. Remove `.caret` from CSS
3. Refactored pipeline graph toggle to display the correct fontawesome caret (Had to change some JavaScript for this)  

## Are there points in the code the reviewer needs to double check?

*  Need to check if I missed any pages 😥 or for any side effects

## Why was this MR needed?
Resolves UI inconsistency

## Screenshots (if relevant)
Before (1 example out of many):
![Screen_Shot_2016-09-12_at_3.49.58_PM](/uploads/5eb93bbcc00412a5875e39302f4d8ba0/Screen_Shot_2016-09-12_at_3.49.58_PM.png)

After:
![Screen_Shot_2016-09-12_at_3.49.48_PM](/uploads/9259a9ebfb0bd09b4cfd55674e9b8be4/Screen_Shot_2016-09-12_at_3.49.48_PM.png)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?
Closes #21169

See merge request !6314

Only hide deploy status external link on x-small screens.

## What does this MR do?

Fixes [a regression](https://gitlab.com/gitlab-org/gitlab-ce/commit/03ea01946524a74773b24430c81804c2724b84b6#68dead621eaa630b5150a4d71b59fa3cd19030fd_57_50) where the deploy status widget hides only the text within the widget, and only for screens within bootstrap's 'small' range (≥544px - <768px).
 
## Are there points in the code the reviewer needs to double check?

I changed the viewport width range to hide the widget from `sm` to `xs` because when the external link is removed, it seems to fit comfortably even on xs viewports. 

Given that we were already hiding the external link (along with all of the deploy text) on `sm` viewports, I assume it's okay to hide the external link still, instead of wrapping it to a new line. 

We could remove the conditional hiding altogether though, and allow the external link to wrap. Definitely doesn't look as nice, but if it's important to show the external link along with the deploy status, we could make it look better when it wraps.

## Why was this MR needed?

Looked buggy, and prevented context being given for build passed icon on smaller screens.

## Screenshots (if relevant)

Before: 

![57efae92cd57c192075546](/uploads/22b278756de4ca6ab3949a4a9692994e/57efae92cd57c192075546.gif)

After: 

![57efaeb41b211194979047](/uploads/b178ddfbbdcfe74d2ce9f52e989a6878/57efaeb41b211194979047.gif)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] API support added
- Tests
  - [ ] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?
https://gitlab.com/gitlab-org/gitlab-ce/issues/22778

cc: @jschatz1

See merge request !6633

[ci skip]

Closes https://gitlab.com/gitlab-org/omnibus-gitlab/issues/1433

See !6543.

Signed-off-by: Rémy Coutable <remy@rymai.me>

Added CC0 license to list of licenses

Adds a "license" (actually a deed, because its a dedication to the public domain) to the appropriate place in the documentation.

It adds another relevant license to our documentation.

See merge request !6622

Issue boards new issue form

## What does this MR do?

Adds a new issue form into the issue boards lists.

## Screenshots (if relevant)

![Screen_Shot_2016-10-03_at_14.57.30](/uploads/17fe6cd37bd020a2ee1688e0b496c18f/Screen_Shot_2016-10-03_at_14.57.30.png)

![Screen_Shot_2016-10-03_at_14.57.32](/uploads/c3f12bcb9ff9a0e7ce5b0bb06dfb0dd7/Screen_Shot_2016-10-03_at_14.57.32.png)

## What are the relevant issue numbers?

Part of #21219

See merge request !6653

Revert "Label list shows all issues (opened or closed) with that label"

## What does this MR do?

Revert changes made on https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5991. Reasoning here: https://gitlab.com/gitlab-org/gitlab-ce/issues/21691#note_16516861

## Does this MR meet the acceptance criteria?

- [X] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [X] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- Tests
  - [X] Added for this feature/bug
  - [ ] All builds are passing
- [X] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [X] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [X] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

Closes #21691

See merge request !6695

Signed-off-by: Rémy Coutable <remy@rymai.me>

MergeRequest new form load diff asynchronously

## What does this MR do?

Don't return diff tab content from the server when request for a new merge request

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?

To avoid 502 errors due to this controller action takes to much time

## What are the relevant issue numbers?

Relates #13912

## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- ~~[ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)~~
- ~~[ ] API support added~~
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5844

Fix broken handling of certain calls in GitHub importer client

## What does this MR do?
It changes/fixes the behavior of request handling in GH client. Now it returns the response directly if it's not a collection of resources. Otherwise, it checks for a passed block, if true, then it yield each page to said block, if not, it collects all response in a single array then returns it.

Closes #22998

See merge request !6703

API: Use Grape DSL to document access requests and members endpoints

Part of #21979, depends on gitlab-org/gitlab-ce!6267 and gitlab-org/gitlab-ce!6266.

See merge request !6269

See !6096.

Issue Board API support

## What does this MR do?

Adds support for Issue Board in the API.

## Are there points in the code the reviewer needs to double check?

~~Double check whether the Issue Board list movement fix is needed.~~ 

*Moved to a separate issue.* [#22890](https://gitlab.com/gitlab-org/gitlab-ce/issues/22890)

## Why was this MR needed?

Currently the API offers partial support to a project's Issue Board indirectly through Labels.
This MR adds support for listing, creating, moving and removing board lists.

## Does this MR meet the acceptance criteria?

- [X] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [X] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [X] API support added
- Tests
  - [X] Added for this feature/bug
  - [X] All builds are passing
- [X] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [X] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [X] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [X] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?
[#22195](https://gitlab.com/gitlab-org/gitlab-ce/issues/22195)

See merge request !6646

Signed-off-by: Rémy Coutable <remy@rymai.me>

Added validation so the user shouldnt be able to submit the form without the title present

Stop issue being dragged if it doesn't have an ID

This is because contributors can't create issues with labels

Changed how the data is passed into Vue resource

Added for attribute to title label

This was causing issues with moving from the done list

Fixed issue when dragging cards

Closes #21219

Gitlab::Redis bigger connection pool on sidekiq workers

See merge request !6657