Documentation: Adapt matomo tracking code

Author: t-b

docu/sphinx/source/_static/js/matomo.js

@@ -8,6 +8,8 @@
     var u="https://www.byte-physics.de/piwik/";
     _paq.push(['setTrackerUrl', u+'piwik.php']);
     _paq.push(['setSiteId', '1']);
+    _paq.push(['setCookieDomain', '*.byte-physics.de']);
+    _paq.push(['setDomains', '*.byte-physics.de']);
     var d=document, g=d.createElement('script'), s=d.getElementsByTagName('script')[0];
     g.type='text/javascript'; g.async=true; g.defer=true; g.src=u+'piwik.js'; s.parentNode.insertBefore(g,s);
   })();