Beef dat README [WIP - not ready to merge yet]

Getting setup to work on code is difficult with the existing state of the README. Let's flesh it out better to make working on the front-end much easier for anyone who wants to do so. :sparkles: :boom: :zap:

### [RENDERED](https://github.com/HospitalRun/frontend/blob/readme-updates/README.md)

:heart: :cake: :pencil: :cake: :heart:

Addresses #2