Backport panels.scss styles from EE

See merge request !12206

Add table for files in merge request diffs

See merge request !12047

Show private subgroups if member of parent group

Closes #32135

See merge request !11764

Call Capybara.reset_sessions! before block_and_wait_for_requests_complete

Closes #33779

See merge request !12224

This adds an ID-less table containing one row per file, per merge request
diff. It has a column for each attribute on Gitlab::Git::Diff that is serialised
currently, with the advantage that we can easily query the attributes of this
new table.

It does not migrate existing data, so we have fallback code when the legacy
st_diffs column is present instead. For a merge request diff to be valid, it
should have at most one of:

* Rows in this new table, with the correct merge_request_diff_id.
* A non-NULL st_diffs column.

It may have neither, if the diff is empty.

Rename "Slash commands" to "Quick actions"

Closes #27070

See merge request !11811

Remove issuable drag and drop and sorting from milestone view

Closes #20900

See merge request !11950

Add missing bottom border to blame age legend

Closes #33739

See merge request !12205

Missing translations for the project & repository pages.

Closes #33420

See merge request !12052

capybara/rspec already calls Capybara.reset_sessions! in an
`after` hook, but `block_and_wait_for_requests_complete` is called
before it so by calling it explicitely here, we prevent any new
requests from being fired.
See
https://github.com/teamcapybara/capybara/blob/ffb41cfad620de1961bb49b1562a9fa9b28c0903/lib/capybara/rspec.rb#L20-L25Signed-off-by: Rémy Coutable <remy@rymai.me>

Document the Delete Merged Branches functionality

See merge request !12217

Create responsive mobile view for pipelines table

Closes #31415

See merge request !12171

Add French translations for Cycle Analytics, Project, and Repository pages.

Closes #32998 and #33140

See merge request !12200

Speed up used languages calculation on charts page

See merge request !12212

set ENV['prometheus_multiproc_dir'] in config/boot.rb instead of config.ru

See merge request !12201

We removed calls from our code to Rugged::Repository#fetch_attributes:
<https://gitlab.com/gitlab-org/gitlab_git/commit/340e111e040ae847b614d35b4d3173ec48329015>

However, we didn't remove calls from within Linguist. This method is only called
when calculating the languages for a repository on the Charts page:
<https://github.com/github/linguist/blob/v4.7.0/lib/linguist/lazy_blob.rb#L33-L36>

We can safely use our own Gitlab::Git::Attributes here. On staging, for the
GitLab CE repo, this makes the calculation take about a third of the time:

    # Before
    Benchmark.realtime do
      Linguist::Repository.new(repository.rugged,
                               repository.rugged.head.target_id).languages
    end
    #=> 23.67193900188431

    # After
    Benchmark.realtime do
      Linguist::Repository.new(repository.rugged,
                               repository.rugged.head.target_id).languages
    end
    #=> 8.945212290156633

Wait for all Ajax and Vue requests to complete in JavaScript tests

Closes #33756

See merge request !12203

Convdev docs

See merge request !12189

Clarify job selection algorithm docs

See merge request !12199

Use the same way to invalidate cache from EE

See merge request !12187

Expose correct path to group

See merge request !12176

Fix intermittent spec failures in spec/finders/pipelines_finder_spec.rb

See merge request !12207

[ci skip]

Replace PhantomJS with Chrome in Karma test runner (2nd attempt)

Closes #33633

See merge request !12144

Issue board docs

See merge request !12197

Jira integ docs

See merge request !12196

Confidential issues redesign docs

See merge request !12195