Delete the user in a GDPR compatible way (#1151)

* Delete the user in a GDPR compatible way

* Block user from calls

* Style fix

app/Models/Enums/UserState.php

@@ -11,6 +11,7 @@ class UserState extends Enum
     public const REJECTED = 2;
     public const ON_LEAVE = 3;
     public const SUSPENDED = 4;
+    public const DELETED = 5;
 
     protected static $labels = [
         self::PENDING   => 'user.state.pending',
@@ -18,5 +19,6 @@ class UserState extends Enum
         self::REJECTED  => 'user.state.rejected',
         self::ON_LEAVE  => 'user.state.on_leave',
         self::SUSPENDED => 'user.state.suspended',
+        self::DELETED   => 'user.state.deleted',
     ];
 }