Updated docs, added options

General Notes:
* Tried to get everything under 80 chars for row width

Template changes:
* Added `ufw allow 443` so Ansible will be accessible immediately after the deployment for Managed Cloud customers.  Will do no harm for core cloud customers.
* Added username and URL as outputs to make it easier for users to figure out how to login if they are unfamiliar with Tower.
* Added Performance Flavors and set the 1 GB performance instance as the default flavor

Doc Changes:
* Updated docs to include new outputs.
* Listed having an already registered nova key as a requirement.  Optionally, we could change it to generate a new keypair.