kvm config in compute nodes by puppet fact

Tested for config sanity -- that the fact returns true on bare metal when it should, and false otherwise if vmx or svm flags are not present, and that the right thing happens with the quickstack::nova::compute node when running in a non-kvm VM (i.e: grep -P '^virt_type' /etc/nova/nova.conf shows
virt_type=qemu
 ).