pgmanager: Add create_conn_listen() which should be used with wait_for_notify. Update wait_for_notify() to not use put_conn(). Add name to ConnectionInfo. Log queries before they are called. Log exceptions. Add notifyexample.
### named connectionsdatabases = { 'test' : 'host=127.0.0.1 user=test password=test dbname=test'}### meta database# connection string (dsn) to meta dbmeta_db = 'host=10.8.0.1 dbname=central'# query from meta db, input is database name (will be placed instead of %s), output is values for create_connmeta_query = '''SELECT host, port, dbname, user, password FROM config.databases WHERE name = %s LIMIT 1'''