The so-postgres-backup script and its cron were living under
salt/backup/config_backup.sls, which meant the backup script and cron
were deployed independently of whether postgres was enabled/disabled.
- Relocate salt/backup/tools/sbin/so-postgres-backup to
salt/postgres/tools/sbin/so-postgres-backup so the existing
postgres_sbin file.recurse in postgres/config.sls picks it up with
everything else — no separate file.managed needed.
- Remove postgres_backup_script and so_postgres_backup from
salt/backup/config_backup.sls.
- Add cron.present for so_postgres_backup to salt/postgres/enabled.sls
and the matching cron.absent to salt/postgres/disabled.sls so the
cron follows the container's lifecycle.