This modifies the edx_ansible role to dump a clean var
file on disk that can be used for subsequent update runs
so that config vars will not be lost

also changes the ansible tmp directory to /var/tmp which is a better
location than using $HOME (used for debugging mostly)

We never used this function.

If we already have an AMI for a particular configuration, use that instead of
requesting a new one.

Also renaming the deploy_* plays to the play name

also adding certs and discern to provision