Add a django-channels/react.js front-end

Created by: lwm

A work in progress. I've never really dealt with react.js, but here we go.

Following on from https://github.com/giving-a-fuck-about-climate-change/carbon-doomsday/issues/5#issuecomment-310872334.

Patching things together from:

• https://codyparker.com/django-channels-with-react/4/
• http://owaislone.org/blog/webpack-plus-reactjs-and-django/
  • https://github.com/ezhome/django-webpack-loader

Will close https://github.com/giving-a-fuck-about-climate-change/carbondoomsday/issues/33.