N°8771 - Add Symfony form component to iTop core (#760)

- Add Symfony Form Component
- Add Symfony CSRF security component
- Add iTop default form template
- Add Twig debug extension to Twig Environment
- Add iTop abstract controller facility to get form builder
- Add Twig filter to make trans an alias of dict_s filter

lib/symfony/security-core/Exception/UnsupportedUserException.php

@@ -0,0 +1,22 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Security\Core\Exception;
+
+/**
+ * This exception is thrown when an account is reloaded from a provider which
+ * doesn't support the passed implementation of UserInterface.
+ *
+ * @author Johannes M. Schmitt <schmittjoh@gmail.com>
+ */
+class UnsupportedUserException extends AuthenticationServiceException
+{
+}