Feature/merge 3 0 develop (#298)

* merging 3.0 into develop

* N°5102 - Allow to send emails (eg. notifications) using GSuite SMTP and OAuth
* migration to iTop 3.1

Co-authored-by: Eric Espie <eric.espie@combodo.com>

lib/league/oauth2-google/examples/reset.php

@@ -0,0 +1,7 @@
+<?php
+
+$provider = require __DIR__ . '/provider.php';
+
+unset($_SESSION['token'], $_SESSION['state']);
+
+header('Location: /');