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>

templates/pages/backoffice/oauth/Landing.ready.js.twig

@@ -0,0 +1,7 @@
+{# @copyright   Copyright (C) 2010-2022 Combodo SARL #}
+{# @license     http://opensource.org/licenses/AGPL-3.0 #}
+
+window.addEventListener("message", function (event){
+    event.source.postMessage(window.location.href, event.origin);
+    window.close();
+}, false);