Merge branch 'pendo-poc' into 'master'

Pendo POC

See merge request gitlab-org/gitlab-ee!14040

app/views/layouts/_head.html.haml

@@ -78,3 +78,4 @@
   = render 'layouts/google_analytics' if extra_config.has_key?('google_analytics_id')
   = render 'layouts/piwik' if extra_config.has_key?('piwik_url') && extra_config.has_key?('piwik_site_id')
   = render_if_exists 'layouts/snowplow'
+  = render_if_exists 'layouts/pendo' if Feature.enabled?(:pendo_tracking) && !Rails.env.test?

ee/app/views/layouts/_pendo.html.haml

+-# haml-lint:disable InlineJavaScript
+:javascript
+  (function(apiKey){
+    (function(p,e,n,d,o){var v,w,x,y,z;o=p[d]=p[d]||{};o._q=[];
+    v=['initialize','identify','updateOptions','pageLoad'];for(w=0,x=v.length;w<x;++w)(function(m){
+        o[m]=o[m]||function(){o._q[m===v[0]?'unshift':'push']([m].concat([].slice.call(arguments,0)));};})(v[w]);
+        y=e.createElement(n);y.async=!0;y.src='https://cdn.pendo.io/agent/static/'+apiKey+'/pendo.js';
+        z=e.getElementsByTagName(n)[0];z.parentNode.insertBefore(y,z);})(window,document,'script','pendo');
+
+        // Call this whenever information about your visitors becomes available
+        // Please use Strings, Numbers, or Bools for value types.
+        pendo.initialize({
+            visitor: {
+              id: '#{current_user&.username}',
+              email: '#{current_user&.email}'
+            }
+        });
+        })('a311ff3e-ad8e-4afb-6ffc-87b0d62305b7');