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/FormExtensionInterface.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;
+
+/**
+ * Interface for extensions which provide types, type extensions and a guesser.
+ */
+interface FormExtensionInterface
+{
+    /**
+     * Returns a type by name.
+     *
+     * @param string $name The name of the type
+     *
+     * @throws Exception\InvalidArgumentException if the given type is not supported by this extension
+     */
+    public function getType(string $name): FormTypeInterface;
+
+    /**
+     * Returns whether the given type is supported.
+     *
+     * @param string $name The name of the type
+     */
+    public function hasType(string $name): bool;
+
+    /**
+     * Returns the extensions for the given type.
+     *
+     * @param string $name The name of the type
+     *
+     * @return FormTypeExtensionInterface[]
+     */
+    public function getTypeExtensions(string $name): array;
+
+    /**
+     * Returns whether this extension provides type extensions for the given type.
+     *
+     * @param string $name The name of the type
+     */
+    public function hasTypeExtensions(string $name): bool;
+
+    /**
+     * Returns the type guesser provided by this extension.
+     */
+    public function getTypeGuesser(): ?FormTypeGuesserInterface;
+}