Implement state recovery, make ask before reload opt-in

src/app/app.component.ts

@@ -17,10 +17,12 @@ export class AppComponent implements OnInit {
 
   ngOnInit() {
     this.titleService.setTitle(this.documentTitle);
-    window.addEventListener('beforeunload', (event) => {
-      const confirmationMessage = 'Refreshing this page may mess up your challenge/tutorial state. Are you sure?';
-      event.returnValue = confirmationMessage;
-      return confirmationMessage;
-    });
+    if (config.dashboard.askReloadSite) {
+      window.addEventListener('beforeunload', (event) => {
+        const confirmationMessage = 'Refreshing this page may mess up your challenge/tutorial state. Are you sure?';
+        event.returnValue = confirmationMessage;
+        return confirmationMessage;
+      });
+    }
   }
 }