Get all namespace names
        Return {'status': true, 'namespaces': [...]} on success
        Return {'error': ...} on error

def rpc_get_all_namespaces( self, **con_info ):
        """
        Get all namespace names
        Return {'status': true, 'namespaces': [...]} on success
        Return {'error': ...} on error
        """
        db = get_db_state(self.working_dir)
        all_namespaces = db.get_all_namespace_ids()
        db.close()

        return self.success_response( {'namespaces': all_namespaces} )