Virtualized nvme-of test case for nvme-stas

[Mateus Rodrigues de Morais]

This task was recommended as a TODO during the nvme-stas MIR review (https://pad.lv/2026591).

Original comment:

  We are currently in discussions to make it easier for software that needs
  special hardware to get into main. And this is IMHO such a case. Gladly it
  only provides usability sugar over what components that are already in main
  (kernel, libnvme, nvme-cli) already provide. But I've not heard about testing
  on actual nvme-of hardware. I'd like to ask you to read through [1][2] where
  we list some ideas how a case like that could be overcome.
  As often there are so many alone the lower transport nvmet-rdma or a real
  adapter loading qla2xxx adapter or nvme_tcp - but one would be better than
  none; Maybe you can even test this fully virtual - think of two qemu guests,
  one with emulated NVME which it provides via nvme_tcp and the other the client
  that does access it, test write/loads some and disconnects. Add the auto
  discovery of stafd/stacd on top and this might be great.
  To be clear - all that this package adds - is tested well, so this is only
  a recommended task but if possible would help to QA the whole stack regularly.

  [1]: https://github.com/canonical/ubuntu-mir/pull/31
  [2]: https://github.com/canonical/ubuntu-mir/issues/30