move logout from oidc to new file

interface.php

@@ -100,7 +100,9 @@
 	<div class="info">
 	  <a href="#" onclick="load(this, 'about.htm')">Über HAWKI</a>
 	  <a href="#" id="feedback" onclick="load(this, 'userpost.php')">Feedback</a>
-	  <a href="logout.php">Abmelden (<?php echo $_SESSION['username']?>)</a>
+	  <a href=<?php if(isset($_SESSION['oidc'])){
+		echo "logout_oidc.php";
+		} else echo "logout.php" ?>>Abmelden (<?php echo $_SESSION['username']?>)</a>
 	  <br>
 	  <a href="/datenschutz" target="_blank" >Datenschutz</a>
 	  <a href="/impressum" target="_blank">Impressum</a>

logout.php

@@ -1,11 +1,5 @@
 <?php
 session_start();
-if(isset($_SESSION['oidc'])){
-    $oidc = $_SESSION['oidc'];
-    unset($_SESSION['oidc']);
-    $oidc -> sign_out($oidc->getIdToken(), "https://ai.lab.hm.edu/logout.php");
-}
-
 session_destroy();
 header("Location: login.php");
 exit;

logout_oidc.php

@@ -0,0 +1,16 @@
+<?php
+require __DIR__ . '/vendor/autoload.php';
+
+use Jumbojett\OpenIDConnectClient;
+
+session_start();
+$oidc = $_SESSION['oidc'];
+unset($_SESSION['oidc']);
+$oidc -> sign_out($oidc->getIdToken(), "https://ai.lab.hm.edu/logout.php");
+
+
+
+session_destroy();
+header("Location: login.php");
+exit;
+?>