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/error-handler/Internal/TentativeTypes.php

@@ -753,6 +753,7 @@ class TentativeTypes
             'isVariadic' => 'bool',
             'isStatic' => 'bool',
             'getClosureThis' => '?object',
+            'getClosureCalledClass' => '?ReflectionClass',
             'getClosureScopeClass' => '?ReflectionClass',
             'getDocComment' => 'string|false',
             'getEndLine' => 'int|false',