Refactor searching and use PostgreSQL trigram indexes for significantly improved performance
Related issue: https://gitlab.com/gitlab-org/gitlab-ce/issues/13743.
Also fixes #12410 (closed)
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Related issue: https://gitlab.com/gitlab-org/gitlab-ce/issues/13743.
Also fixes #12410 (closed)