Enable postgresql slot replication
Our current replication setup is not using replication slots, so it's really hard to have the right number of WAL segments to keep around, and this is leaving us with a replication model that just doesn't work.
We should just use our toolset properly and enable replication slots so our standby servers can get up to speed whenever they need to, removing the need to restart the replication to recover.
cc/ @gl-infra