File Systems: EFS for /home and/or /scratch

For the 1.0 release, we want to add some additional options that are setup at cluster build time.

While the default and the tutorial will focus on "bare metal" style NFS served from the SMS server, we want to make other features of AWS optionally available.

Here, we want to add additional options to have either /home or /scratch served via EFS instead of NFS. 