Add ability to edit forms and add new fields

This commit adds the ability to edit and modify existing forms.
On the technical side, it also adds a new reusable validation Facade which helps reduce duplicated code.

app/Policies/FormPolicy.php

@@ -57,7 +57,7 @@ class FormPolicy
      */
     public function update(User $user, Form $form)
     {
-        // unused
+        return $user->can('admin.hiring.forms');
     }
 
     /**