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/FormEvent.php

@@ -0,0 +1,55 @@
+<?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;
+
+use Symfony\Contracts\EventDispatcher\Event;
+
+/**
+ * @author Bernhard Schussek <bschussek@gmail.com>
+ */
+class FormEvent extends Event
+{
+    private FormInterface $form;
+    protected $data;
+
+    public function __construct(FormInterface $form, mixed $data)
+    {
+        $this->form = $form;
+        $this->data = $data;
+    }
+
+    /**
+     * Returns the form at the source of the event.
+     */
+    public function getForm(): FormInterface
+    {
+        return $this->form;
+    }
+
+    /**
+     * Returns the data associated with this event.
+     */
+    public function getData(): mixed
+    {
+        return $this->data;
+    }
+
+    /**
+     * Allows updating with some filtered data.
+     *
+     * @return void
+     */
+    public function setData(mixed $data)
+    {
+        $this->data = $data;
+    }
+}