Migrations for Cycle Analytics backend

See merge request gitlab-org/gitlab-ee!15061

This change lays the foundation for customizable cycle analytics stages.
The main reason for the change is to extract the event definitions to
separate objects (start_event, end_event) so that it could be easily
customized later on.

Only read rebase status from the model

See merge request gitlab-org/gitlab-ce!31847

Prior to 12.1, rebase status was looked up directly from Gitaly. In
https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/14417 , a DB
column was added to track the status instead. However, we couldn't stop
looking at the gitaly status immediately, since some rebases may been
running across the upgrade.

Now that we're in 12.3, it is safe to remove the direct-to-gitaly
lookup. This also happens to fix a 500 error that is seen when viewing
an MR for a fork where the source project has been removed.

We still look at the Gitaly status in the service, just in case Gitaly
and Sidekiq get out of sync - I assume this is possible, and it's a
relatively cheap check.

Since we atomically check and set `merge_requests.rebase_jid`, we
should never enqueue two `RebaseWorker` jobs in parallel.

Fix job scheduling when extra CI minutes purchased

See merge request gitlab-org/gitlab-ee!15120

Removes db/fixtures from database files

See merge request gitlab-org/gitlab-ce!31635

This will avoid Danger to suggest a database review for files inside
db/fixtures

Merge branch '50020-allow-email-notifications-to-be-disabled-for-all-users-of-a-group' into 'master'

Allow email notifications to be disabled for all users of a group

See merge request gitlab-org/gitlab-ce!30755

- Adds UI to configure in group and project settings
- Removes notification configuration for users when
disabled at group or project level

Merge branch '50020-allow-email-notifications-to-be-disabled-for-all-users-of-a-group-ee' into 'master'

Allow email notifications to be disabled for all users of a group

See merge request gitlab-org/gitlab-ee!15026

- Adds UI to configure in group and project settings
- Removes notification configuration for users when
disabled at group or project level

Upgrade Rugged to 0.28.3.1

See merge request gitlab-org/gitlab-ce!31794

Remove duplicate -/users/terms routes

See merge request gitlab-org/gitlab-ce!31812

Allow CI to clone public projects when HTTP protocol is disabled

Closes #65805

See merge request gitlab-org/gitlab-ce!31632

Eliminate many Gitaly calls in discussions API

Closes #65957

See merge request gitlab-org/gitlab-ce!31834

Extra CI minutes purchased where not considered when
namespace inherited application-wide Runners minutes
limit.

Previously, the API to retrieve discussions from merge requests often
generated hundreds of Gitaly calls to determine whether a system note
should be shown to the user. It did this by:

1. Rendering the Markdown
2. Extracting cross-references from the Markdown
3. For cross-references that were commits, a Gitaly FindCommit RPC
   would be issued to validate that the commit exists.

The last step is unnecessary because we don't need to display a commit
if the user doesn't have access to the project in the first place.

`RendersNotes#prepare_notes_for_rendering` is already used in
`MergeRequestsController`, which is why we don't see N+1 Gitaly calls
there. We use it here to optimize the note redaction process.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/65957

Adds EE prepend, which for some reason was missing

See merge request gitlab-org/gitlab-ce!31851

This is a security release:
https://github.com/libgit2/libgit2/releases

Exclude json content type from workhorse interception

See merge request gitlab-org/gitlab-ce!31809

Remove :puma_phase metrics

See merge request gitlab-org/gitlab-ce!31773

Remove failing obsolete karma spec

Closes #13550

See merge request gitlab-org/gitlab-ee!15208

Remove prepend_if_ee from CE codebase

See merge request gitlab-org/gitlab-ce!31845

This was added in
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/31789

Merge branch '13494-todo-s-not-rendering-when-there-is-a-design-management-related-todo-ce' into 'master'

CE backport of gitlab-org/gitlab-ee!15129 (Allow Todos to link to Designs)

See merge request gitlab-org/gitlab-ce!31789

Merge branch '13494-todo-s-not-rendering-when-there-is-a-design-management-related-todo' into 'master'

Allow Todos to link to Designs

Closes #13494

See merge request gitlab-org/gitlab-ee!15129

Allow to use focus: true in specs

See merge request gitlab-org/gitlab-ce!31691