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/user.php

@@ -0,0 +1,39 @@
+<?php
+
+$provider = require __DIR__ . '/provider.php';
+
+if (isset($_GET['logout']) && 1 == $_GET['logout']) {
+    unset($_SESSION['token']);
+}
+
+if (!empty($_SESSION['token'])) {
+    $token = unserialize($_SESSION['token']);
+}
+
+if (empty($token)) {
+    header('Location: /');
+    exit;
+}
+
+try {
+    // We got an access token, let's now get the user's details
+    $userDetails = $provider->getResourceOwner($token);
+
+    // Use these details to create a new profile
+    printf('Hello %s!<br/>', $userDetails->getFirstname());
+} catch (Exception $e) {
+    // Failed to get user details
+    exit('Something went wrong: ' . $e->getMessage());
+}
+
+// Use this to interact with an API on the users behalf
+echo "Token is: <tt>", $token->getToken(), "</tt><br/>";
+
+// Use this to get a new access token if the old one expires
+echo "Refresh token is: <tt>", $token->getRefreshToken(), "</tt><br/>";
+
+// Number of seconds until the access token will expire, and need refreshing
+echo "Expires at ", date('r', $token->getExpires()), "<br/>";
+
+// Allow the user to logout
+echo '<a href="?logout=1">Logout</a><br/>';