constructor(icon, id, title, init, onselect) {
		const emptyFunc = () => {};
		this.#container = <div className="container"></div>;
		this.#icon = <Icon icon={icon} id={id} title={title} />;
		this.#id = id;
		this.#title = title;
		this.#init = init || emptyFunc;
		this.#onselect = onselect || emptyFunc;
		this.#init(this.#container);
	}
Creates a new sidebar app.
@param {string} icon
@param {string} id
@param {string} title
@param {(el:HTMLElement)=>void} init
@param {(el:HTMLElement)=>void} onselect