Provisioning virtual machines on KVM (libvirt)

[Lennonka]

https://theforeman-foreman-documentation-preview-pr-3922.surge.sh/nightly/Provisioning_Hosts/index-foreman-el.html#Provisioning_Virtual_Machines_on_KVM_kvm-provisioning

I don't like the focus on KVM. In Foreman we always talk about libvirt, not KVM. KVM is an internal implementation detail.

It's also confusing that in the prerequisites there's:

Optional: The examples in these procedures use the root user for KVM. If you want to use a non-root user on the KVM server, you must add the user to the libvirt group on the KVM server:

But this is only required if libvirt is on the same machine as Foreman.

For upstream it's also missing the instruction to install the libvirt compute resource. You can use the same procedure as "Installing VMware plugin" but the command is foreman-installer --enable-foreman-compute-libvirt.

Configuring Foreman server for KVM connections

This should be rephrased to mention it's only for adding remote libvirt connections. It's not needed if libvirt is on the same system.

Originally posted by @ekohl in #3922 (review)