Resolve "MR "Check out branch" button should be disabled when the source branch is deleted"

Closes #42255

See merge request gitlab-org/gitlab-ce!16631

Improve Nginx configuration files

See merge request gitlab-org/gitlab-ce!16605

Mute notifications in the seeder to speed GDK development

See merge request gitlab-org/gitlab-ce!16747

Fix MR revert check when no merged_at is present

See merge request gitlab-org/gitlab-ce!16760

After source branch deletion the Merge request `Check out branch` button is disabled.

Fix JS equality rules in some specs

See merge request gitlab-org/gitlab-ce!16734

More conversions of $.ajax to axios

See merge request gitlab-org/gitlab-ce!16731

i18n flash message

Set alternate object directories in run_git

See merge request gitlab-org/gitlab-ce!16715

Resolve "Make tests running bundle install for gitaly more flexible"

Closes #42290

See merge request gitlab-org/gitlab-ce!16654

Digital Ocean Spaces now supports AWS v4 streaming API

See merge request gitlab-org/gitlab-ce!16745

See https://github.com/fog/fog-aws/issues/428#issuecomment-360869183

Generalize toggle_buttons for JavaScript usage

See merge request gitlab-org/gitlab-ce!16689

Fix spec failures in issues_spec.rb

Closes #42488

See merge request gitlab-org/gitlab-ce!16744

Include the GitLab version info when commercial content on help page is disabled

Closes #42486

See merge request gitlab-org/gitlab-ce!16743

Part of https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/4110

Merge branch '42327-import-from-gitlab-com-fails-destination-already-exists-and-is-not-an-empty-directory-error' into 'master'

Resolve "Import from GitLab.com fails (destination already exists and is not an empty directory error)."

Closes #42327

See merge request gitlab-org/gitlab-ce!16714

Moves components into vue files:

See merge request gitlab-org/gitlab-ce!16719