Updating README.md 

More information about what this repository is about and who should use it - what the prerequisites are, etc.
half-finished. Still need to update "how to use these playbooks"

Half-finished version of README.md. Some considerations and background info added. Specifically for AAROC sites.
Started work on a quickstart guide. 

Started work on a quickstart guide. Should perhaps be moved later to a wiki or separate file.
Merge pull request #2 from AAROC/certified

Certified