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/Loader/ChoiceLoaderInterface.php

@@ -0,0 +1,72 @@
+<?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\Loader;
+
+use Symfony\Component\Form\ChoiceList\ChoiceListInterface;
+
+/**
+ * Loads a choice list.
+ *
+ * The methods {@link loadChoicesForValues()} and {@link loadValuesForChoices()}
+ * can be used to load the list only partially in cases where a fully-loaded
+ * list is not necessary.
+ *
+ * @author Bernhard Schussek <bschussek@gmail.com>
+ */
+interface ChoiceLoaderInterface
+{
+    /**
+     * Loads a list of choices.
+     *
+     * Optionally, a callable can be passed for generating the choice values.
+     * The callable receives the choice as only argument.
+     * Null may be passed when the choice list contains the empty value.
+     *
+     * @param callable|null $value The callable which generates the values
+     *                             from choices
+     */
+    public function loadChoiceList(?callable $value = null): ChoiceListInterface;
+
+    /**
+     * Loads the choices corresponding to the given values.
+     *
+     * The choices are returned with the same keys and in the same order as the
+     * corresponding values in the given array.
+     *
+     * Optionally, a callable can be passed for generating the choice values.
+     * The callable receives the choice as only argument.
+     * Null may be passed when the choice list contains the empty value.
+     *
+     * @param string[]      $values An array of choice values. Non-existing
+     *                              values in this array are ignored
+     * @param callable|null $value  The callable generating the choice values
+     */
+    public function loadChoicesForValues(array $values, ?callable $value = null): array;
+
+    /**
+     * Loads the values corresponding to the given choices.
+     *
+     * The values are returned with the same keys and in the same order as the
+     * corresponding choices in the given array.
+     *
+     * Optionally, a callable can be passed for generating the choice values.
+     * The callable receives the choice as only argument.
+     * Null may be passed when the choice list contains the empty value.
+     *
+     * @param array         $choices An array of choices. Non-existing choices in
+     *                               this array are ignored
+     * @param callable|null $value   The callable generating the choice values
+     *
+     * @return string[]
+     */
+    public function loadValuesForChoices(array $choices, ?callable $value = null): array;
+}