[CE] Group bulk edit issues/mrs/epics - change label

See merge request gitlab-org/gitlab-ce!31193

- Original EE MR: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/14827

Add possibilty to view starrers ("stargazers") of a repository & any user's starred repositories

Closes #20137

See merge request gitlab-org/gitlab-ce!24690

Add docs for reject_unsigned_commits (premium only)

See merge request gitlab-org/gitlab-ce!31113

Split api resources into it's own doc

See merge request gitlab-org/gitlab-ce!31597

Move the api resources section from the api readme
to it's own file, and adjust/link accordingly

Specify time frame in metrics page

See merge request gitlab-org/gitlab-ce!31283

Pass keyname instead of translated string

Add missing report-uri to CSP config

See merge request gitlab-org/gitlab-ce!31593

Checksum clair executable

See merge request gitlab-org/gitlab-ce!31423

Expose time since starring on project/:id/starrers API endpoint; exclude private profiles here as well

Fix API endpoint for starred projects of a user; add info about starred projects on profile to documentation