Add UEFI PXEboot test instructions to simp-doc

I looked for the documentation to figure out how to test, instead of searching through closed tickets, and found no documentation. I do not know why this ticket was closed.

See and for examples of the instructions needed to create a libvirt client and to set up the network.

Discussion of lack of UEFI PXE boot support https://forums.virtualbox.org/viewtopic.php?f=9&t=84349