9722: Revert ES6 changes to url_builder
9722: Revert ES6 changes to url_builder

Webpacker can't seem to compile any assets outside of app/javascript
(and only supports one single entry point).

Similar issue: https://stackoverflow.com/q/50982724/763231

thecartercenter/elmo,thecartercenter/elmo,thecartercenter/elmo