Re-introduce the old homepage at '/' and move new homepage to '/new-homepage'

Elements of new homepage design are still in flux.
To facilitate integrating the work done so far on the new homepage,
re-introduce the old homepage and serve that at '/' and serve
the new homepage design at '/new-homepage'

h/static/scripts/site.js

@@ -22,7 +22,7 @@ document.addEventListener('DOMContentLoaded', function () {
 
   // setup route
   var route = document.location.pathname;
-  if (route.match('^/$')) {
+  if (route.match('^/(new-homepage)?$')) {
     installerController.showSupportedInstallers(document);
   } else if (route.match('^/groups') === 0) {
     setupGroupsController(route);