Allow to use Dockerfile templates

See merge request !7247

Move admin application spinach test to RSpec

Part of #23036

See merge request !8140

Move admin deploy keys spinach test to RSpec

Part of #23036

See merge request !8141

Always use `fixture_file_upload` helper to upload files in tests.

## What does this MR do?

Fix a broken spec.

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

## Why was this MR needed?

## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- [ ] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] 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 it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

See merge request !8164

* Also is not a good idea to use File.open without closing the file
  handler. We should use it with a block or close it explicitly.

Update NGINX configuration files to add websocket support

## What does this MR do?

Changes the bundled NGINX configuration files to support websockets introduced in https://gitlab.com/gitlab-org/gitlab-workhorse/merge_requests/83

These changes are also going into omnibus: https://gitlab.com/gitlab-org/omnibus-gitlab/merge_requests/1146

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

Best to wait until the omnibus MR is merged as the method may be changed.

## Why was this MR needed?

Without it, NGINX won't let websockets through to workhorse.

## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- Tests
  - [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 it does - 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?

Related to #22864

See merge request !8039

Correct mattermost slash commands pretty path

## What does this MR do?

Corrects the pretty path used for mattermost slash commands.

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

## Why was this MR needed?

## Screenshots (if relevant)

![Screen_Shot_2016-12-14_at_13.31.18](/uploads/61b0cbe11bf747d566ed7959efa704b8/Screen_Shot_2016-12-14_at_13.31.18.png)

## Does this MR meet the acceptance criteria?

- [ ] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] 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 it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

See merge request !8085

Add new runner script attempts docs and update .gitlab-ci.yml

Related: https://gitlab.com/gitlab-org/gitlab-ci-multi-runner/issues/1907 and https://gitlab.com/gitlab-com/infrastructure/issues/685

Adds missing docs about the new script attempts variables in the runner.

See merge request !8100

Enable Style/MultilineOperationIndentation in Rubocop

Fixes #25741

See merge request !8125

https://gitlab.com/gitlab-org/gitlab-ce/issues/23036

https://gitlab.com/gitlab-org/gitlab-ce/issues/23036

Mattermost session

This branch is based of tag v8.14.4 so I could test on an instance better.

But stuck on the tests, as setting up the whole doorkeeper stuff doesn't seem to be supported for testing.

See merge request !8033

Cleaner merge commit messages

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/23462

See merge request !7722

Add sorting functionality for group/project members

## What does this MR do?

This MR adds sort functionality to group/project members list.

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

No.

## Why was this MR needed?

This MR helps the user to manage and find users of a group/project fast. It also improves UX.

## Screenshots (if relevant)

**Before**
![before-pr-member](/uploads/412bfdfddc63e48a62e2095d664660b5/before-pr-member.png)

**After**
![pr-after](/uploads/ae23a5c7689b46d26a948f22a0ac2360/pr-after.png)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG.md) entry 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 it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

Closes #21622 


Closes #23573

See merge request !7032

Avoid use of Hash#dig to keep compatibility with Ruby 2.1

See merge request !8153

Refactor Bitbucket importer to use BitBucket API Version 2

## What does this MR do?

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

## Why was this MR needed?

## What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ce/issues/19946

## Screenshots (if relevant)

This MR needs the following permissions in the Bitbucket OAuth settings:

![image](/uploads/a26ae5e430a724bf581a92da7028ce3c/image.png)

- [] 

## Does this MR meet the acceptance criteria?

- [ ] [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
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] 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)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5995