Loads all plugins advertising entry points with the given group name.
        The specified plugin needs to be a callable that accepts the everest
        configurator as single argument.

def load_all(self, group):
        """
        Loads all plugins advertising entry points with the given group name.
        The specified plugin needs to be a callable that accepts the everest
        configurator as single argument.
        """
        for ep in iter_entry_points(group=group):
            plugin = ep.load()
            plugin(self.__config)