Update playground with configurable data and updated styleguide (#875)
Update playground with configurable data and updated styleguide (#875)

## Changes

- Allows you to configure the auth and user data
- Saves data in cookies
- Updates styling to newer [styleguide](https://styleguide.auth0.com)

**Screenshot**

![screencapture-localhost-3000-2018-11-20-10_50_35](https://user-images.githubusercontent.com/855223/48795738-9270cd00-ecb2-11e8-9fae-060a113b533a.png)

auth0/auth0.js,auth0/auth0.js,auth0/auth0.js