remove analytics

per discussion in 2020 on the steering council list
https://groups.google.com/u/1/g/jupyter-steering/c/7j7F0lyQY84/m/Ch9Qj9nMAAAJ

_includes/head.html

@@ -36,16 +36,5 @@
     <![endif]-->
     <script src="//use.typekit.net/kpd5yrh.js"></script>
     <script>try{Typekit.load();}catch(e){}</script>
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-      })(window,document,'script','//www.google-analytics.com/analytics.js','ga');
-
-      ga('create', 'UA-52617120-1', 'auto', {'storage': 'none'});
-      ga('set', 'anonymizeIp', true);
-      ga('send', 'pageview');
-
-    </script>
     <script>console.log('Welcome to Project Jupyter! Explore the various tools available and their corresponding documentation. If you are interested in contributing to the platform, please visit the community resources section at https://jupyter.org/community.html.')</script>
 </head>