Revert postgres logical replication deltaas

This reverts two commits:

    0bb8e41
    "Fix postgres schema after dropping old tables (#16730)"

and

    51e4e35
    "Add a Postgres `REPLICA IDENTITY` to tables that do not have an implicit one. This should allow use of Postgres logical replication. (take  2, now with no added deadlocks!) (#16658)"

and also amends the changelog.

Author: David Robertson