Support images with QEMU "--enable-kvm" flag

[Mierdin]

In reviewing nre-learning/nrelabs-curriculum#275, I tried to run the PoC lesson contained therein using the new Vagrant selfmedicate setup, and ran into this:

Could not access KVM kernel module: No such file or directory
qemu-system-x86_64: failed to initialize KVM: No such file or directory

We should modify the setup script to ensure the right packages and kernel mods are installed and loaded, in order to support this (as we do in NRE Labs production).

This might be a little more complicated as we consider compatibilities with VirtualBox, etc - but we should still do what we can to support this.