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/form/ClearableErrorsInterface.php

@@ -0,0 +1,29 @@
+<?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\Form;
+
+/**
+ * A form element whose errors can be cleared.
+ *
+ * @author Colin O'Dell <colinodell@gmail.com>
+ */
+interface ClearableErrorsInterface
+{
+    /**
+     * Removes all the errors of this form.
+     *
+     * @param bool $deep Whether to remove errors from child forms as well
+     *
+     * @return $this
+     */
+    public function clearErrors(bool $deep = false): static;
+}