PR #849: network model selection for libvirt
I added support to libvirt VM creation to specify a network model.
As stated, I did this because I needed it. The list is currently hardcoded, not something I like, if need be I can extract the hardcoded list to a Setting.
In my own foreman, it's actually currently a text field, but I think a dropdown would be better.
fixes #2944 - nic type selection for libvirt
defaults to 'virtio'
I needed this in my own setup because virtio was being buggy and would
crash my apt mirror VM. switching to e1000 fixed.
I don't particularly care for the device models being hardcoded. I would
of course prefer that it be queried from the libvirt itself, but I don't
see a way to do that.