Feature/clarify for sharing with other engineers

This branch is for setting-up the ./server.pem key linkage (and documentation) only. This playbook will not run without an additional "external_vars.yml" file. Another branch/pull request will be used to update the configure.py script to assist int the external_vars.yml configuration (first pass).

However, to test, this command should work (after running configure):
`ssh -i ./server.pem ec2-user@<your ip address to test>`