Merge branch '9800-500-error-when-trying-to-update-project-surpassing-repository-limit-through-the-web-interface' into 'master'

Resolve "500 error when trying to update project surpassing repository limit through the Web interface"

Closes #9800

See merge request gitlab-org/gitlab-ee!9579

Docs: Fix all Kubernetes and Runner related anchors

See merge request gitlab-org/gitlab-ce!25063

Show alerts settings only for manual configuration

See merge request gitlab-org/gitlab-ee!9538

We should hide alerts settings from GitLab-managed Prometheus
instances and show them only in manual mode.

Refs https://gitlab.com/gitlab-org/gitlab-ee/issues/9258#note_132612251

Fix diff files not rendering

See merge request gitlab-org/gitlab-ce!25358

Enable persisted pipeline stages by default

Closes #57610

See merge request gitlab-org/gitlab-ce!25347

Fixes some diff files not rendering when the renderIt
property is updated.
Previously it was using a local copy of renderIt which meant
Vue wouldn't update it when the files renderIt property was updates

Fix Projects::MergeRequests::DiffsController specs

See merge request gitlab-org/gitlab-ce!25253

This reverts commit 481938de.

* This will upload the sha of the docker image containing assets to
  assist with building specific sha builds in the future.
* Addresses: gitlab-org/release/framework#51

Docs: add index for /customization/*

See merge request gitlab-org/gitlab-ce!25298

Same as `branded_login_page.md`

Docs: add index for /customization/*

See merge request gitlab-org/gitlab-ee!9578

Same as `branded_login_page.md`

Make the file tree in merge requests resizable

Closes #51857

See merge request gitlab-org/gitlab-ce!25097

Fix typo in troubleshooting steps for "local issuer certificate" error

See merge request gitlab-org/gitlab-ce!25341

Update custom MR templates for gitlab-ce

See merge request gitlab-org/gitlab-ce!25227

Externalize strings from `/app/views/projects/commit`

See merge request gitlab-org/gitlab-ce!24668

Docs: article: End-to-end testing with WebdriverIO and GitLab CI/CD

Closes gitlab-com/community-writers#159

See merge request gitlab-org/gitlab-ce!19834

End-to-end testing example

See merge request gitlab-org/gitlab-ce!18959

Docs: article: End-to-end testing with WebdriverIO and GitLab CI/CD

See merge request gitlab-org/gitlab-ee!6131

End-to-end testing example

See merge request gitlab-org/gitlab-ce!18959

Allow blank values to be stored in reactive cache

See merge request gitlab-org/gitlab-ce!25283

Reactive caching concern was using .present? to determine if it got
a valid value from the cache. This returns false for values such as
false, [], {}. Change this check to !.nil? instead.

These specs were flaky and only passing after a retry due to how
rspec-retry works.

1. The test with paths that don't exist was returning 200 on the first
  try, then 404 on the second, not because the paths don't exist, but
  because the MR IID didn't change, thus the MR couldn't be found.
  I decided to remove the test entirely since we don't seem to return
  404 for paths that don't exist.
2. The test with a user that cannot view the merge request was failing
  the first time because the project owner wasn't removed with
  `project.team.truncate`.
  Changing the `let(:user)` to `create(:user)` and calling
  `project.add_maintainer(user)` in the `before` block fix the test.
Signed-off-by: Rémy Coutable <remy@rymai.me>

Quarantine GEO tests

See merge request gitlab-org/gitlab-ee!9589

Fix job name overflow in Firefox, Safari and IE

Closes #56426

See merge request gitlab-org/gitlab-ce!24707