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/console/Output/BufferedOutput.php

@@ -16,14 +16,12 @@ namespace Symfony\Component\Console\Output;
  */
 class BufferedOutput extends Output
 {
-    private $buffer = '';
+    private string $buffer = '';
 
     /**
      * Empties buffer and returns its content.
-     *
-     * @return string
      */
-    public function fetch()
+    public function fetch(): string
     {
         $content = $this->buffer;
         $this->buffer = '';
@@ -32,7 +30,7 @@ class BufferedOutput extends Output
     }
 
     /**
-     * {@inheritdoc}
+     * @return void
      */
     protected function doWrite(string $message, bool $newline)
     {