Detect UEFI enabled KVM instances on import

[adietrich-ussignal]

The required feature described as a wish

As an operator, I would like to have the KVM import instances functionality provide the ability to detect if the instance is UEFI SECURE enabled.

There are two lines that appear to help decipher whether an instance has secure boot enabled, and can help pre-fill the necessary instance settings without having to modify those by stopping the instance.

  <os>
    <loader readonly='yes' secure='yes' type='pflash'>/usr/share/OVMF/OVMF_CODE_4M.secboot.fd</loader>
    <nvram template='/usr/share/OVMF/OVMF_VARS_4M.ms.fd'>/var/lib/libvirt/qemu/nvram/de71dfe1-7027-413f-bf23-75b40237e861.fd</nvram>
  </os>

[weizhouapache]

fixed by #11218

thanks @shwstppr for the fix