Register a new authentication method

            name
                the name of the authentication method, typically displayed by the webapp

            input_to_display

            Only available after that the Plugin Manager is loaded

def register_auth_method(self, auth_method):
        """
            Register a new authentication method

            name
                the name of the authentication method, typically displayed by the webapp

            input_to_display

            Only available after that the Plugin Manager is loaded
        """
        if not self._loaded:
            raise PluginManagerNotLoadedException()
        self._user_manager.register_auth_method(auth_method)