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/ChoiceList/View/ChoiceGroupView.php

@@ -0,0 +1,44 @@
+<?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\ChoiceList\View;
+
+/**
+ * Represents a group of choices in templates.
+ *
+ * @author Bernhard Schussek <bschussek@gmail.com>
+ *
+ * @implements \IteratorAggregate<array-key, ChoiceGroupView|ChoiceView>
+ */
+class ChoiceGroupView implements \IteratorAggregate
+{
+    public $label;
+    public $choices;
+
+    /**
+     * Creates a new choice group view.
+     *
+     * @param array<ChoiceGroupView|ChoiceView> $choices the choice views in the group
+     */
+    public function __construct(string $label, array $choices = [])
+    {
+        $this->label = $label;
+        $this->choices = $choices;
+    }
+
+    /**
+     * @return \Traversable<array-key, ChoiceGroupView|ChoiceView>
+     */
+    public function getIterator(): \Traversable
+    {
+        return new \ArrayIterator($this->choices);
+    }
+}