finish removing analytics and related helper (#2309)

It was still present in one file, previous
commit just removed the prefetch.

Also remove dnt_helper, it was used only by analytics.

Refs: #2305
Refs: nodejs/node#23083
Refs: nodejs/node#22652
Refs: #2302

external/survey-2018/index.html

@@ -2245,22 +2245,5 @@ <h4><i>(Top Impacts)</i></h4>
   <script src="d3.v3.min.js"></script>
   <script src="data.min.js"></script>
   <script src="full.min.js"></script>
-
-  <script src="/static/js/dnt_helper.js"></script>
-  <script>
-    (function(){
-      if (!_dntEnabled()) {
-        !function(n,o,d,e,j,s){n.GoogleAnalyticsObject=d;n[d]||(n[d]=function(){
-        (n[d].q=n[d].q||[]).push(arguments)});n[d].l=+new Date;j=o.createElement(e);
-        s=o.getElementsByTagName(e)[0];j.async=1;j.src='//www.google-analytics.com/analytics.js';
-        s.parentNode.insertBefore(j,s)}(window,document,'ga','script');
-
-        if (!ga) return;
-
-        ga('create', 'UA-67020396-1', 'auto');
-        ga('send', 'pageview');
-      }
-    })();
-  </script>
 </body>
 </html>

layouts/partials/footer.hbs

@@ -51,5 +51,3 @@
     s.parentNode.insertBefore(m,s);
   })(document,'script');
 </script>
-
-<script src="/static/js/dnt_helper.js"></script>

package.json

@@ -27,7 +27,6 @@
   "standard": {
     "ignore": [
       "static/js/modernizr.custom.js",
-      "static/js/dnt_helper.js",
       "static/legacy/*",
       "external"
     ]