Update GTAG

- Update to the new GTAG

Author: Svetlana Karslioglu

_templates/layout.html

@@ -1,5 +1,15 @@
 {% extends "!layout.html" %}
 
+{%- block extrahead %} {% endblock %}
+
+<!-- Google Tag Manager -->
+<script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
+new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
+j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
+'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
+})(window,document,'script','dataLayer','GTM-T8XT4PS');</script>
+<!-- End Google Tag Manager -->
+
 {%- block content %}
 {{ super() }}
 <script>
@@ -11,6 +21,16 @@
 </script>
 {%- endblock %}
 
+{%- block body -%}
+
+<!-- Google Tag Manager (noscript) -->
+<noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-T8XT4PS"
+height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>
+<!-- End Google Tag Manager (noscript) -->
+
+{{ super() }}
+{% endblock %}
+
 {% block footer %}
 {{ super() }}
 <script>