This adapts the README to describe the necessary tooling. And adds
a qemutest vm to use libvirt as provider (instead of vbox).
Runs fine as demonstrated in P802.
First iteration failed without the gpg dependency ~> P800 Thus why the
post-install.sh adds it directly as a workaround (in this diff).
Ideally, this should be added in our manifest somewhere or even better in the
puppet module which requires it but I don't know which one is pulling
it ¯\_(ツ)_/¯. In the mean time, that sounds reasonable.
Note: As P801 shows, it is not required for the vbox template and I don't know
why this worked for it.
Depends on D4137
Related to T2606