It is no longer required to add IP addresses to the Vagrant-generated ssh
configuration because the Vagrant-configured hostnames now match up with the
names morph will try to use to connect to the VMs.

Remove the VirtualBox GUI, see
https://search.nixos.org/options?channel=21.05&show=virtualisation.virtualbox.host.headless&from=0&size=50&sort=relevance&query=virtualbox

... if you are reading this not in the repo, but from the web page, you might
not know where to go to make all those nice commands work.

... if other hypervisors are installed as well.

Co-Authored-By: Jean-Paul Calderone <jean-paul@privatestorage.io>