Don't send rejection mails for all auto-generated mails

Closes #28472

See merge request !13254

Ensure we run installation Rake tasks in a clean env in TestEnv

Closes #35859

See merge request !13249

This would be much more accurate. We assume this is an
auto-generated email if such header is provided, and
the value is not "no". It could also be: "auto-generated",
"auto-replied", or other values from extension. It seems
that only "no" could mean that this is sent by a human.

See: https://tools.ietf.org/html/rfc3834

Do not validate CSRF token in API unless needed

Closes #35705

See merge request !13256

Remove test gitaly when older than version file

See merge request !13250

Fly-out dropdown menu in new sidebar

Closes #34026

See merge request !12938

Fix Prometheus application settings help link to point to Prometheus help page

Closes #33921

See merge request !13258

Disable the Rails/Delegate cop

Closes #35869

See merge request !13267

Empty project factory by default

See merge request !13260

See https://gitlab.com/gitlab-org/gitlab-ce/issues/35869 for the
rationale.
Signed-off-by: Rémy Coutable <remy@rymai.me>

Change project FK migration to skip existing FKs

Closes #35243

See merge request !13235

Signed-off-by: Rémy Coutable <remy@rymai.me>

If we call `system('rake', 'taks_name')`, `ENV['RUBYOPT']` is set to
`'-rbundler/setup'` but some tasks (e.g. `gitlab:gitaly:install` need
a clean env since they install their own Gem bundle.
Signed-off-by: Rémy Coutable <remy@rymai.me>

Also make it easier to have mailer helper

Add icons to project sidebar

Closes #34027 and #35877

See merge request !13204

Uniquify reserved word usernames on OAuth user creation

See merge request !13244

Synchronous zanata community contribution translation

Closes #35003

See merge request !13242

Show auto-generated avatars in Groups dashboard tree for Groups without avatars

See merge request !13188

Make Delete Merged Branches handle wildcard protected branches correctly

Closes #35592

See merge request !13251

Update milestone docs CE

See merge request !13233

The "Delete Merged Branches" button should filter out protected
branches matching the wildcard patterns.

Closes gitlab-org/gitlab-ce#35592.

This changes the migration ProjectForeignKeysWithCascadingDeletes so
that it does not add already existing foreign keys and indexes, making
it easier to re-run the migration.

Expose target_iid in Events API

See merge request !13247

Extending API for protected branches

See merge request !12756

Add rugged_is_ancestor method

See merge request !13232

Fix Issue board when using Ruby 2.4

Closes #35769

See merge request !13220

Make the 'issuables list meta-data' shared example less dangerous

See merge request !13236

Ensure all project factories use `:repository` trait or `:empty_project`

See merge request !13238