If guests have the following capabilities, automatic NFS client
installation will be done:
* nfs_client_installed - Checks if the NFS client is installed
* nfs_client_install - Install the NFS client
Support is already in for Debian, Ubuntu, RedHat, CentOS, and Fedora
I don't use `activated` here because I'd really like to optimize
performance as much as possible, and loading files from disk is
generally slow. So instead of using `activated` I load the file at the
last possible moment which is when the exact class is being requested.
I don't think many people will do this outside of the core, and I'm not
too concerned.