N°6934 - Symfony 6.4 - upgrade Symfony bundles to 6.4 (#580)

* Update Symfony lib to version ~6.4.0
* Update code missing return type
* Add an iTop general configuration entry to store application secret (Symfony mandatory parameter)
* Use dependency injection in ExceptionListener & UserProvider classes

lib/symfony/twig-bundle/DependencyInjection/Compiler/RuntimeLoaderPass.php

@@ -21,6 +21,9 @@ use Symfony\Component\DependencyInjection\Reference;
  */
 class RuntimeLoaderPass implements CompilerPassInterface
 {
+    /**
+     * @return void
+     */
     public function process(ContainerBuilder $container)
     {
         if (!$container->hasDefinition('twig.runtime_loader')) {