def get(self):
        """List existing config namespaces and their items"""
        namespaces = db.ConfigNamespace.order_by(
            ConfigNamespace.sort_order,
            ConfigNamespace.name
        ).all()

        return self.make_response({
            'message': None,
            'namespaces': namespaces
        }, HTTP.OK)
List existing config namespaces and their items