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-kernel/DependencyInjection/ConfigurableExtension.php

@@ -27,16 +27,15 @@ use Symfony\Component\DependencyInjection\ContainerBuilder;
  */
 abstract class ConfigurableExtension extends Extension
 {
-    /**
-     * {@inheritdoc}
-     */
-    final public function load(array $configs, ContainerBuilder $container)
+    final public function load(array $configs, ContainerBuilder $container): void
     {
         $this->loadInternal($this->processConfiguration($this->getConfiguration($configs, $container), $configs), $container);
     }
 
     /**
      * Configures the passed container according to the merged configuration.
+     *
+     * @return void
      */
     abstract protected function loadInternal(array $mergedConfig, ContainerBuilder $container);
 }