fix a path which was missed by 0abd0f4a
drop product version number where we don't need it

This will reduce the number of search and replace occurrences for the
future.
clarify NAT requirement is for VirtualBox provider only
-DEPS iso got renamed to be shared between Cloud 3, 4, and 5
add libvirt settings
make network configuration specific per-provider
switch from Cloud 3 to Cloud 4