Add high level instructions for hosting p6 on AWS and Azure (maybe Google)

[simon-temple]

As developers move toward production deployment they may want to run p6 on one of the common hosting services. We should document:

1. The role of the proxy and the firewall rule implications for hosted p6 instances
2. The need to disable the local 'development' p6proxy
3. Basic deployment example on AWS and Azure with a few firewall config screen shots to help.