Docs: Added source upgrade guides for 12.0.0

See merge request gitlab-org/gitlab-ce!29795

Document Usage Quotas group settings page

Closes #63022

See merge request gitlab-org/gitlab-ce!29599

Add zoom call section in issue data page

See merge request gitlab-org/gitlab-ce!29815

Add changelog entry for the new operations_feature_flags_clients.token_encrypted column

See merge request gitlab-org/gitlab-ce!29820

We missed to add this in
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/29320.

Related to https://gitlab.com/gitlab-org/gitlab-ce/issues/57918

Unquarantine merge tests

Closes gitlab-org/quality/nightly#93 and gitlab-org/quality/nightly#94

See merge request gitlab-org/gitlab-ce!29833

Crosslink Mattermost integrations, simplify components list

See merge request gitlab-org/gitlab-ce!29317

Allow developers to delete tags

Closes #52954

See merge request gitlab-org/gitlab-ce!29668

This commit adds
 - feature specs
  - to test the ability of a user with "developer" permission
    to delete tags in repositories.
 - documentation

Fix Container Scanning job with K8S runners

Closes gitlab-ee#11448

See merge request gitlab-org/gitlab-ce!29706

Add note about not translating API messages.

See merge request gitlab-org/gitlab-ce!29748

Add identity information to external authorization requests

See merge request gitlab-org/gitlab-ce!29461

Issue: https://gitlab.com/gitlab-org/gitlab-ce/issues/61201#

Fix missing API notification flags for Microsoft Teams

See merge request gitlab-org/gitlab-ce!29824

Demote new section

See merge request gitlab-org/gitlab-ce!29829

Un-quarantine OAuth spec

Closes gitlab-org/quality/nightly#100

See merge request gitlab-org/gitlab-ce!29764

Remove support for app label matching

See merge request gitlab-org/gitlab-ce!29460

Removes database.yml.example

See merge request gitlab-org/gitlab-ce!29822

It's an empty file that was committed by accident on
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/28565

From now on, only match on the annotations, instead of falling back to
legacy app label. This enables users to use the app label for other
purposes such as helm charts.

Cache feature flag names in Redis for a minute

Closes #63435

See merge request gitlab-org/gitlab-ce!29816

Adds docs for job collapsible sections

See merge request gitlab-org/gitlab-ce!29792

Update response code for container registry api bulk delete

Closes #62183

See merge request gitlab-org/gitlab-ce!29448

The bulk delete api endpoint for container registries can
only be called once per hour. If a user calls the endpoint more
than once per hour, they will now receive a 400 error with a
descriptive message.

Added IP restriction docs to groups

See merge request gitlab-org/gitlab-ce!29809

We saw on GitLab.com, the SQL query, `SELECT "features"."key" FROM
"features"` peaked at 2300 times per second.

We can quiet this down a bit by caching it in Redis for a minute.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/63435

Revert concurrent pipeline creation for pipeline schedules

See merge request gitlab-org/gitlab-ce!29794