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/routing/Generator/Dumper/GeneratorDumper.php

@@ -20,17 +20,14 @@ use Symfony\Component\Routing\RouteCollection;
  */
 abstract class GeneratorDumper implements GeneratorDumperInterface
 {
-    private $routes;
+    private RouteCollection $routes;
 
     public function __construct(RouteCollection $routes)
     {
         $this->routes = $routes;
     }
 
-    /**
-     * {@inheritdoc}
-     */
-    public function getRoutes()
+    public function getRoutes(): RouteCollection
     {
         return $this->routes;
     }