Backport Admin menu changes from EE

See merge request gitlab-org/gitlab-ce!21864

Doesn't synchronize default branch for push mirrors

Closes #51725

See merge request gitlab-org/gitlab-ce!21861

Using path syntax to include Admin namespace as part of Project
controller menu expansion code, in order to not conflict with same
controller name but in Geo namespace.

Align form labels following Bootstrap 4 docs

See merge request gitlab-org/gitlab-ce!21752

We should not synchronize the source repository with
the target root ref while updating a push mirror.

Correct grammar (setup to set-up) in Docs

See merge request gitlab-org/gitlab-ce!21857

Allows to sort projects by most stars

Closes #47203

See merge request gitlab-org/gitlab-ce!21762

Cycle Analytics - Fix broken feature page link

See merge request gitlab-org/gitlab-ce!21855

Rename some css classes that are shared between issues and mrs

See merge request gitlab-org/gitlab-ce!21856

Add note about projects when user is deleted

See merge request gitlab-org/gitlab-ce!21843

Fix leading slash in redirects and add cop

Closes #37423 and #50645

See merge request gitlab-org/gitlab-ce!21828

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Correct Gitlab Capitalization in code files

See merge request gitlab-org/gitlab-ce!21841

Merge branch '47398-user-is-unable-revoke-a-authorized-application-unless-user-oauth-applications-is-checked-in-admin-settings' into 'master'

Resolve "User is unable revoke a Authorized application unless User OAuth applications is checked in admin settings"

Closes #47398

See merge request gitlab-org/gitlab-ce!21835

[ci skip]

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Fix activity titles for MRs in chat notification services

Closes gitlab-ee#5325

See merge request gitlab-org/gitlab-ce!21834

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Fix long webhook URL overflow for custom integration

Closes #41040

See merge request gitlab-org/gitlab-ce!21668

Gitaly servers require the GitLab Shell secret

See merge request gitlab-org/gitlab-ce!21847

Fix broken link to modal component source

See merge request gitlab-org/gitlab-ce!21830

Enable frozen string in app/controllers/**/*.rb

See merge request gitlab-org/gitlab-ce!21736

Add Fog use_iam_profile option to docs

See merge request gitlab-org/gitlab-ce!21844

Add Gitlab::Database::Subquery.self_join to delete_all with limit

See merge request gitlab-org/gitlab-ce!21839

Update wiki upload documentation

See merge request gitlab-org/gitlab-ce!21815

Add webhook branch filtering docs

See merge request gitlab-org/gitlab-ce!21816

QA: Fix failure in merge_merge_request_from_fork_spec.rb

Closes #51657

See merge request gitlab-org/gitlab-ce!21817