Enable CI for gitlab when .gitlab-ci.yml is pushed
Make enabling CI as easy as pushing file.
Should be merged after !1402 (merged).
Fixes #2650 (closed). Part of #2594 (closed) and internal issue https://dev.gitlab.org/gitlab/gitlabhq/issues/2528
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Make enabling CI as easy as pushing file.
Should be merged after !1402 (merged).
Fixes #2650 (closed). Part of #2594 (closed) and internal issue https://dev.gitlab.org/gitlab/gitlabhq/issues/2528