Add data protection statement.

js/matomo.js

@@ -1,6 +1,7 @@
 var _paq = _paq || [];
-_paq.push(['trackPageView']);
 _paq.push(['enableLinkTracking']);
+_paq.push(['disableCookies']);
+_paq.push(['trackPageView']);
 (function() {
   var u="//www.bovender.de/piwik/";
   _paq.push(['setTrackerUrl', u+'piwik.php']);