document how to run a quick test via qemu

[leggewie]

sudo apt install ovmf qemu-system-x86
wget https://dl.armbian.com/uefi-x86/Noble_cloud_minimal-qcow2
qemu-system-x86_64 -bios /usr/share/ovmf/OVMF.fd -m 2048 -display gtk,gl=on -device virtio-net,netdev=net0 -netdev user,id=net0,hostfwd=tcp::5800-:22 -drive if=none,id=root,file=./Noble_cloud_minimal-qcow2,format=qcow2 -device virtio-blk,drive=root

success!

not sure where this should go in the docs, so opening a ticket instead for now.

maybe good to explain the various switches just a little bit.