Add max_replication_slots to PG HA documentation

Closes #65700

See merge request gitlab-org/gitlab-ce!31534

Add database guidelines for background migrations and update queries

See merge request gitlab-org/gitlab-ce!31190

- Add a new guideline regarding the file location of background
migrations
- Add a new section about execution timing guidelines for all different
kinds of migrations

Docs: Clarify without authentication

Closes #60157

See merge request gitlab-org/gitlab-ce!31604

Merge branch 'ce-9510-new-metric-button-should-not-be-duplicated-on-custom-metrics-page' into 'master'

CE: Remove duplicated 'New metric' button in Prometheus configuration

See merge request gitlab-org/gitlab-ce!31394

- Remove "new metrics" duplicated button and replace with a message
- Replace css with utility classes in the prometheus metrics view
- Remove unused css

Remove label issue and MR counts from default API responses

See merge request gitlab-org/gitlab-ce!31543

Corrected custom email hostname instructions

See merge request gitlab-org/gitlab-ce!31646

Add contribution section to contribution agreements

See merge request gitlab-org/gitlab-ce!30510

Replace `gitlab-rake` with `gitlab-backup` command for backup and restore tasks

See merge request gitlab-org/gitlab-ce!31555

Add namespace default note to cluster docs

Closes #65751

See merge request gitlab-org/gitlab-ce!31596

Update Migration Style Guide. Remove MySQL mentions

See merge request gitlab-org/gitlab-ce!31531

Add a field for released_at to GH importer

See merge request gitlab-org/gitlab-ce!31496

Sorting in alphabetical order, adding strings to be used with analyzers

See merge request gitlab-org/gitlab-ce!31510

Bring k8s cheat sheet to docs

See merge request gitlab-org/gitlab-ce!31319

Bring the support team k8s cheat sheet into the
main documentation

Update rails project template

See merge request gitlab-org/gitlab-ce!31310

Add link to memory team page from the installation requirements

See merge request gitlab-org/gitlab-ce!31637

Rename githost.log -> git_json.log

See merge request gitlab-org/gitlab-ce!31634

Clean up an incomplete thought as a spec

See merge request gitlab-org/gitlab-ce!31541

Filter title, description, and body from logs

Closes #64460 and #60365

See merge request gitlab-org/gitlab-ce!31274

CE port of https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/14981

See merge request gitlab-org/gitlab-ce!31493

The githost.log name was often confused with GitHost.io. Rename this to
git_json.log to make it clear it's coming from Git and that it's JSON
data.

Enable the prometheus endpoint by default

See merge request gitlab-org/gitlab-ce!31565

Bring scoped environment variables to core

See merge request gitlab-org/gitlab-ce!30779

As decided in https://gitlab.com/gitlab-org/gitlab-ce/issues/53593

CE port of "Rename blocking MRs to cross-project MR dependencies"

See merge request gitlab-org/gitlab-ce!31372

We're removing the ability for MRs in a single project to block each
other, and performing a rename of the feature to go along with that.
This necessitates documentation changes

Refactor subscriptions information

See merge request gitlab-org/gitlab-ce!31504

Docs for local requests whitelist

See merge request gitlab-org/gitlab-ce!31520

- Add documentation under security/webhooks since similar docs are
present there.