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/GeneratorDumperInterface.php

@@ -23,15 +23,11 @@ interface GeneratorDumperInterface
     /**
      * Dumps a set of routes to a string representation of executable code
      * that can then be used to generate a URL of such a route.
-     *
-     * @return string
      */
-    public function dump(array $options = []);
+    public function dump(array $options = []): string;
 
     /**
      * Gets the routes to dump.
-     *
-     * @return RouteCollection
      */
-    public function getRoutes();
+    public function getRoutes(): RouteCollection;
 }