Improve patternfly-react readme content

[dgutride]

We would like to improve the structure of the readme - starting with the main readme at patternfly/patternfly-react/readme.md. The package library readme's will follow at a later date. The recommended format follows:

• Project title
• Brief description — This is the only section that will need writing help
  • Why PatternFly package/philosophy (similar to Why Lodash? & expressjs philosophy) — good bullet points (link to the main README file in repo) “Part of family of packages, learn more about the rest of them)
• Community (quick, nice-looking set of links to repeat in each package)
  • PatternFly website
  • Slack
  • Medium
  • Email distro
• Table of contents (so that as/if the file grows, people can jump to the most relevant sections)
• Links to other README files in the repo — only include in main README file
  • Looking for PF3 info? Take them into branch
• Setup
  • Parent README (Creating first) and individual package README (this is how to use the package)
  • Requirements
  • Installation
  • Usage
• Contribution guidelines
  • How to become a contributor (high level)—1 doc (link from PF site)
  • Contributing to repo—link to each repo’s contribution guidelines README file
• License