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/var-dumper/Resources/bin/var-dump-server

@@ -10,6 +10,10 @@
  * file that was distributed with this source code.
  */
 
+if ('cli' !== PHP_SAPI) {
+    throw new Exception('This script must be run from the command line.');
+}
+
 /**
  * Starts a dump server to collect and output dumps on a single place with multiple formats support.
  *