switch analytics to using matomo

<script src="{{ relative_root_path }}/assets/js/bootstrap.min.js"></script>

<script src="{{ relative_root_path }}/assets/js/lesson.js"></script>

{% if site.kind == "lesson" %}

<!-- Matomo -->

<script>

  (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){

  (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),

  m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)

  })(window,document,'script','https://www.google-analytics.com/analytics.js','ga');

  ga('create', 'UA-37305346-2', 'auto');

  ga('send', 'pageview');

  var _paq = window._paq = window._paq || [];

  /* tracker methods like "setCustomDimension" should be called before "trackPageView" */

  _paq.push(["setDocumentTitle", document.domain + "/" + document.title]);

  _paq.push(["setDomains", ["*.lessons.carpentries.org","*.datacarpentry.github.io","*.datacarpentry.org","*.librarycarpentry.github.io","*.swcarpentry.github.io"]]);

  _paq.push(["setDoNotTrack", true]);

  _paq.push(["disableCookies"]);

  _paq.push(['trackPageView']);

  _paq.push(['enableLinkTracking']);

  (function() {

    var u="https://carpentries.matomo.cloud/";

    _paq.push(['setTrackerUrl', u+'matomo.php']);

    _paq.push(['setSiteId', '1']);

    var d=document, g=d.createElement('script'), s=d.getElementsByTagName('script')[0];

    g.async=true; g.src='//cdn.matomo.cloud/carpentries.matomo.cloud/matomo.js'; s.parentNode.insertBefore(g,s);

  })();

</script>

<!-- End Matomo Code -->

{% endif %}

{% if page.math %}

<script src="{{ relative_root_path }}/assets/js/katex.min.js"></script>