Change image-selector to not use manager

- Now changes the images directly for user, system & cover.
- Extra permission checks added to edit & delete actions.

app/Auth/User.php

@@ -24,7 +24,7 @@ class User extends Model implements AuthenticatableContract, CanResetPasswordCon
      * The attributes that are mass assignable.
      * @var array
      */
-    protected $fillable = ['name', 'email', 'image_id'];
+    protected $fillable = ['name', 'email'];
 
     /**
      * The attributes excluded from the model's JSON form.