Added staged files state to IDE

Closes #44842, #44844, and gitlab-ee#4541

See merge request gitlab-org/gitlab-ce!17898

Fix direct_upload for old records

See merge request gitlab-org/gitlab-ce!18360

Old records have a null value of file_store column.
This causes the problems with current direct_upload implementation,
as this makes it to choose Store::REMOTE instead of Store::LOCAL.

This change moves the store save when change saving the object.

Upgrading gitlab-gollum-lib and rouge

See merge request gitlab-org/gitlab-ce!18436

Resolve "Calculating total size of a project's CI artifacts"

Closes #41059

See merge request gitlab-org/gitlab-ce!17839

[Rails5] Avoid type casting in uniqueness validator

See merge request gitlab-org/gitlab-ce!18470

Previously we scheduled a worker to just some this but we were running
into performance issues when the build table was getting too large. So
now we've updated the code such that this column is updated immediately
and incremented/decremented by the correct amount whenever artifacts are
created or deleted.

We've also added the performance optimization that we do not update this
statistic if a project is deleted because it could result in many
updates for a project with many builds.

Fix label links update on project transfer

Closes #44158

See merge request gitlab-org/gitlab-ce!18320

Resolve "Get rid of branch element all in bottom bar in WEB IDE"

Closes #44834

See merge request gitlab-org/gitlab-ce!18367

Resolve "Show `failure_reason` in jobs view content section"

Closes #44271

See merge request gitlab-org/gitlab-ce!17814

Get GITLAB_FEATURES from Project#licensed_features instead of Namespace#features (#5320)

See merge request gitlab-org/gitlab-ce!18189

This commit does two things:
1. Synchronizes `Gemfile.rails5.lock` with the latest changes in `Gemfile`
2. Adds a monkey patch for active record to avoid type casting in uniqueness
validator.

In Rails 5.0 there was introduced a bug [1] that causes to problems like
this:

```
1) API::Users POST /user/:id/gpg_keys/:key_id/revoke when authenticated revokes existing key
Failure/Error: let(:gpg_key) { create(:gpg_key, user: user) }
TypeError:
  can't cast Hash
```

This bug was fixed in Rails 5.1 [2].

[1]: https://github.com/rails/rails/pull/23523/commits/811a4fa8eb6ceea841e61e8ac05747ffb69595ae
[2]: https://github.com/rails/rails/pull/24745/commits/aa062318c451512035c10898a1af95943b1a3803

Resolve "View labels when editing labels in sidebar and board sidebar"

Closes #34262

See merge request gitlab-org/gitlab-ce!18380

Bump CI to use Chrome V65 and ChromeDriver 2.36

See merge request gitlab-org/gitlab-ce!18459

Revert the addition of goldiloader

See merge request gitlab-org/gitlab-ce!18458

Resolve "Avoid possible infinite loops in Container Scanning"

See merge request gitlab-org/gitlab-ce!18467

Fix code climate example

See merge request gitlab-org/gitlab-ce!18267

Fix issues on groups group trees

Closes #42407

See merge request gitlab-org/gitlab-ce!18390

Fix Custom hooks are not triggered by UI wiki edit

Closes #42354

See merge request gitlab-org/gitlab-ce!18251

Fix DAST example in documentation

See merge request gitlab-org/gitlab-ce!18456

This reverts commit 2c3c5b35.

Revisit this after https://gitlab.com/gitlab-org/gitlab-ce/issues/45441

This reverts the addition of the "goldiloader" Gem and all use of it.
While this Gem is very promising it's causing a variety of problems on
GitLab.com due to it eager-loading too much data in places where we
don't expect/can handle this. At least for the time being this means we
have to go back to manually fixing N+1 query problems, but at least
those should not cause a negative impact on availability.