armvirt (64) with EFI support

[jjak0b]

I think the armvirt support will be very usefull for testing arm-based platforms. The armvirt with EFI stub support will allow developers to test it using virt-manager, libvirt, qemu, etc ... (seems that armvirt require EFI stub to run on libvirt and qemu) on KVM mode.

I ask the support becase some users (including me) would like to use OMR as VM router on devices like RPI-4 or others arch64 based devices that have enough ram and CPU to run it enough smoothly in KVM mode. I built manually the images on v0.58.5 and v0.59.1 versions for 5.4 kernels and they work perfectly as router in a RPI-4 4GB VMs.

The armvirt EFI compile configuration has been discussed in #2296 for another platform, but the config parameters are the same for a generic cortex-a53 target. So a dedicated config file and for auto compiling images for each snapshot and releases would be very usefull.