feat(ui): add main menu navbar and join game functionality (#35)

Reviewed-on: #35
Reviewed-by: lq64 <lq@blackhole.local>
Co-authored-by: Janis <janis.e.20@gmx.de>
Co-committed-by: Janis <janis.e.20@gmx.de>

knockoutwhistweb/app/controllers/UserController.scala

@@ -64,7 +64,7 @@ class UserController @Inject()(
     if (sessionCookie.isDefined) {
       sessionManager.invalidateSession(sessionCookie.get.value)
     }
-    NoContent.discardingCookies(DiscardingCookie("sessionId"))
+    Redirect(routes.UserController.login()).discardingCookies(DiscardingCookie("sessionId"))
   }
 
 }