Don't rename system when migrating from 9.x -> 9.4

Closes #35525 and #36148

See merge request !13228

Bugfix.silence on disabled notifications

Closes #23714

See merge request !13325

Add notes about database performance for MySQL

See merge request !13516

since the mere act of creating the key sends an email :|

since we're just adding them as a member, the permission may still
return false.

and add one

since this is for user invites and the like.

[ci skip]

fix confidential border issue as well as confidential styles leaking on new MR

Closes gitlab-ee#3121

See merge request !13388

Migrate force push check to Gitaly

See merge request !13406

Fixes the correct import modal window not showing

Closes #36318

See merge request !13490

Add option to disable project export on instance

See merge request !13211

Fix formatting of patch_versions.md

See merge request !13503

Better categorize test coverage results

See merge request !13485

Enable Timecop safe mode

Closes #32004

See merge request !13498

Update the markdown unconditionally since the move might have been
done before, but the markdown not updated.

This will be done in
20170717150329_enqueue_migrate_system_uploads_to_new_folder.rb
instead.

Better caching and indexing of broadcast messages

Closes #31706

See merge request !13429

Include the `is_admin` field in the `GET /users/:id` API when current user is an admin

Closes #36213

See merge request !13501

Make Git revision dropdown style consistent

See merge request !13116