Rework subscription-related code for psql and pg_dump

When Who What
2024-12-05 07:56:22 Michael Paquier (michael-kun) Closed in commitfest 2025-01 with status: Committed
2024-12-05 07:56:22 Michael Paquier (michael-kun) Changed committer to michael-kun
2024-11-29 04:24:52 Michael Paquier (michael-kun) Changed authors to Michael Paquier (michael-kun)
2024-11-29 04:24:52 Michael Paquier (michael-kun) Changed targetversion to 18
2024-11-29 04:24:40 Michael Paquier (michael-kun) Attached mail thread Z0lB2kp0ksHgmVuk@paquier.xyz
2024-11-29 04:24:40 Michael Paquier (michael-kun) Created patch record