Clean up Intro course doc
Clean up Intro course doc

https://trello.com/c/f6sj4W74/1408-training-auth0-introduction

auth0/docs,yvonnewilson/docs,jeffreylees/docs,auth0/docs,auth0/docs,yvonnewilson/docs,jeffreylees/docs,yvonnewilson/docs,jeffreylees/docs