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/options-resolver/README.md

@@ -0,0 +1,15 @@
+OptionsResolver Component
+=========================
+
+The OptionsResolver component is `array_replace` on steroids. It allows you to
+create an options system with required options, defaults, validation (type,
+value), normalization and more.
+
+Resources
+---------
+
+ * [Documentation](https://symfony.com/doc/current/components/options_resolver.html)
+ * [Contributing](https://symfony.com/doc/current/contributing/index.html)
+ * [Report issues](https://github.com/symfony/symfony/issues) and
+   [send Pull Requests](https://github.com/symfony/symfony/pulls)
+   in the [main Symfony repository](https://github.com/symfony/symfony)