Add request rate limits

Closes #30053

See merge request gitlab-org/gitlab-ce!14708

Merge branch '40230-groups-gitlab-org-labels-json-redirects-to-groups-gitlab-org-labels-json' into 'master'

Resolve "/groups/gitlab-org/labels.json redirects to /groups/gitlab-org/-/labels/.json"

Closes #40230

See merge request gitlab-org/gitlab-ce!15427

Changing OAuth lookup to be case insensitive

Closes #38822

See merge request gitlab-org/gitlab-ce!15312

Fix hashed storage with project transfers to another namespace

Closes gitlab-ee#4056

See merge request gitlab-org/gitlab-ce!15444

Delete empty fork networks

See merge request gitlab-org/gitlab-ce!15373

Optimise getting the pipeline status of commits

See merge request gitlab-org/gitlab-ce!15332

Fix go-import meta data when enabled_git_access_protocol is a blank string

Closes #40256

See merge request gitlab-org/gitlab-ce!15448

Resolve "Performance issues when loading large number of wiki pages"

Closes #34600

See merge request gitlab-org/gitlab-ce!15276

Exports a couple of project related code as es6 modules

See merge request gitlab-org/gitlab-ce!15356

Convert migration to populate latest merge request ID into a background migration

See merge request gitlab-org/gitlab-ce!15440

Add dropdowns documentation

See merge request gitlab-org/gitlab-ce!15396

This is to smear updates over a few hours to avoid causing excessive
replication lag as seen in https://gitlab.com/gitlab-com/infrastructure/issues/3235.

Update database_debugging.md

See merge request gitlab-org/gitlab-ce!15434

Replace ci_status_path with pipeline_path

See merge request gitlab-org/gitlab-ce!15369

De-duplicate background migration matchers defined in spec/support/migrations_helpers.rb

See merge request gitlab-org/gitlab-ce!15441

Update HA README.md to clarify GitLab support does not troubleshoot DRBD.

See merge request gitlab-org/gitlab-ce!15428