add background listener for sidebar

scripts/GUI/entrypoints/sidebar.js

@@ -1,8 +1,21 @@
 import Sidebar from '/scripts/GUI/sidepanel.js'
 
 export default class ManagedSidebar {
-     constructor () {
-          // WIP
+	static manage() {
+		chrome.runtime.onMessage.addListener(
+			function(request, sender, sendResponse) {
+				if (request.action.includes("sidebar_open")) {
+					ManagedSidebar.enable();
+				}
+			}
+		);
+	}
+	
+	static enable() {
 		new Sidebar(`/pages/popup.htm`);
 	}
+
+	disable() {
+
+	}
 }