revert MAINTAIN and pg_maintain

When Who What
2023-07-07 18:31:13 Nathan Bossart (bossartn) Closed in commitfest 2023-07 with status: Committed
2023-07-07 18:31:13 Nathan Bossart (bossartn) Changed committer to bossartn
2023-06-30 05:14:50 Nathan Bossart (bossartn) Changed authors to Nathan Bossart (bossartn)
2023-06-30 05:14:50 Nathan Bossart (bossartn) Changed targetversion to 16
2023-06-30 05:14:41 Nathan Bossart (bossartn) Attached mail thread E1q7j7Y-000z1H-Hr@gemulon.postgresql.org
2023-06-30 05:14:41 Nathan Bossart (bossartn) Created patch record