Remove pg_hba injection and filtering

Previously we explicitly injected a replication record into pg_hba.conf.
This doesn't allow users to explicitly write their configurations.

This change will just write the lines specified by the user.

postgres2.yml

@@ -56,12 +56,12 @@ postgresql:
     username: postgres
     password: zalando
   pg_hba:
+  - host replication replicator 127.0.0.1/32 md5
   - host all all 0.0.0.0/0 md5
-  - hostssl all all 0.0.0.0/0 md5
+  # - hostssl all all 0.0.0.0/0 md5
   replication:
     username: replicator
     password: rep-pass
-    network: 127.0.0.1/32
   superuser:
     username: postgres
     password: zalando