Handle domain sessions better in QA scenarios

Closes gitlab-qa#102

See merge request gitlab-org/gitlab-ce!15452

Clean up new dropdown styles

Closes #39142 and #39446

See merge request gitlab-org/gitlab-ce!13676

Remove unnecessary js-issuable-edit

Closes #41042

See merge request gitlab-org/gitlab-ce!15883

Use memoization for commits on diffs

See merge request gitlab-org/gitlab-ce!15857

check the import_status field before doing SQL operations to check the import url

See merge request gitlab-org/gitlab-ce!15752

Hide issues and MRs in labels list if disabled

See merge request gitlab-org/gitlab-ce!15863

Move Repository#write_ref to Git::Repository#write_ref

Closes gitaly#793

See merge request gitlab-org/gitlab-ce!15712

Treat empty markdown and html strings as valid cached text, not missing cache…

See merge request gitlab-org/gitlab-ce!15856

The Gitaly CommitService is being hammered by n + 1 calls, mostly when
finding commits. This leads to this gRPC being turned of on production:
https://gitlab.com/gitlab-org/gitaly/issues/514#note_48991378

Hunting down where it came from, most of them were due to
MergeRequest#show. To prove this, I set a script to request the
MergeRequest#show page 50 times. The GDK was being scraped by
Prometheus, where we have metrics on controller#action and their Gitaly
calls performed. On both occations I've restarted the full GDK so all
caches had to be rebuild.

Current master, 806a68a8, needed 435 requests
After this commit, 154 requests

Use Single list for multiple clusters

See merge request gitlab-org/gitlab-ce!15848

Backport a spec fix done in EE (5dbecb8e) to CE

See merge request gitlab-org/gitlab-ce!15842

Treat empty markdown and html strings as valid cached text, not missing cache that needs to be updated

Use message body for merge request description

Closes #40968

See merge request gitlab-org/gitlab-ce!15839

Merge branch '41041-undefined-method-new_project_guidelines_html-unable-to-load-from-cache' into 'master'

Resolve "undefined method `new_project_guidelines_html', unable to load from cache"

Closes #41041

See merge request gitlab-org/gitlab-ce!15878

Clears the current Appearance cache otherwise it breaks since new_project_guidelines_html would be missing

Solves https://gitlab.com/gitlab-org/gitlab-ce/issues/41041.
Signed-off-by: Rémy Coutable <remy@rymai.me>

Add js prefix for issuable-edit

Closes #40965

See merge request gitlab-org/gitlab-ce!15813

Stop "ERROR: TypeError{}" from being logged to the console and fail tests

Closes #37619

See merge request gitlab-org/gitlab-ce!15830

Updated image for diff navigation docs

See merge request gitlab-org/gitlab-ce!15875

Use app host instead of asset host when rendering image blob or diff

Closes #41002

See merge request gitlab-org/gitlab-ce!15854

Merge branch '41023-activerecord-staleobjecterror--attempted-to-update-a-stale-object--ci-build' into 'master'

Job dropping by MissingDependenciesError should consider StaleObjectError

Closes #41023

See merge request gitlab-org/gitlab-ce!15873

Checks for null in job tooltip title

Closes #40997

See merge request gitlab-org/gitlab-ce!15869

Milestone sidebar docs

See merge request gitlab-org/gitlab-ce!15861

Fix migration that removes issues.branch_name

See merge request gitlab-org/gitlab-ce!15858

Clarify casing of I18N placeholder names

See merge request gitlab-org/gitlab-ce!15867

Fix comment on image discussion icon alignment (update icons)

Closes #39608

See merge request gitlab-org/gitlab-ce!15760

rename remaining issue_ prefixed files

See merge request gitlab-org/gitlab-ce!15818

Ignore temporary table in schema

Closes #40976

See merge request gitlab-org/gitlab-ce!15866

Gitaly mirroring migration prep

Closes gitaly#816

See merge request gitlab-org/gitlab-ce!15775

Backport epic in issue

See merge request gitlab-org/gitlab-ce!15799