Accountsdb plugin postgres improvement (#21034)

Summary of Changes

Added the reference postgresql.conf
Prepare slot update statement to reduce overhead in updating slot
Support custom connection string
Allow the plugin to panic on replication issues to ensure consistency

accountsdb-plugin-postgres/scripts/drop_schema.sql

@@ -2,7 +2,7 @@
  * Script for cleaning up the schema for PostgreSQL used for the AccountsDb plugin.
  */
 
-DROP TRIGGER account_update_trigger;
+DROP TRIGGER account_update_trigger ON account;
 DROP FUNCTION audit_account_update;
 DROP TABLE account_audit;
 DROP TABLE account;