Docs: port article to EE
What does this MR do?
Ports https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/13911 and https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/13968 to EE
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Ports https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/13911 and https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/13968 to EE