Guest control: Cleaned methods involved in fetching/handling

- Moves guest user caching from User class to app container for
  simplicity.
- Updates test to use simpler $this->users->guest() method for
  consistency.
- Streamlined helpers to avoid function overlap for simplicity.
- Extracted user profile dropdown while doing changes.

app/Http/Middleware/Authenticate.php

@@ -12,7 +12,7 @@ class Authenticate
      */
     public function handle(Request $request, Closure $next)
     {
-        if (!hasAppAccess()) {
+        if (!user()->hasAppAccess()) {
             if ($request->ajax()) {
                 return response('Unauthorized.', 401);
             }