function Sidebar({ container, toggler }) {
	$sidebar = $sidebar ?? create(container, toggler);
	return $sidebar;
}
Create a sidebar or return the existing one
@param {object} [arg0] - the element that will activate the sidebar
@param {HTMLElement} [arg0.container] - the element that will contain the sidebar
@param {HTMLElement} [arg0.toggler] - the element that will toggle the sidebar
@returns {HTMLElement & SideBar}