Build handbook: add infrastructure maintenance to team responsibilities.
Fixes https://gitlab.com/gitlab-org/omnibus-gitlab/issues/2532
@gitlab-build-team If you had to do any of the written tasks, would you be able to follow the documentation?
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Fixes https://gitlab.com/gitlab-org/omnibus-gitlab/issues/2532
@gitlab-build-team If you had to do any of the written tasks, would you be able to follow the documentation?