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/http-foundation/RequestMatcherInterface.php

@@ -20,8 +20,6 @@ interface RequestMatcherInterface
 {
     /**
      * Decides whether the rule(s) implemented by the strategy matches the supplied request.
-     *
-     * @return bool
      */
-    public function matches(Request $request);
+    public function matches(Request $request): bool;
 }