Add support for ARMv8 to use AAVMF EFI firmware

[dustins]

I discovered I wasn't able to run VMs on my RK3588 (ARM64). Although ARM64 supports UEFI it wasn't able to find appropriate *.fd files because it is assumed every architecture was using OVMF. On ARM64 it should be using AAVMF as far as I can tell.

This PR adds support for using AAVMF on ARMv8 architectures and updates the documentation to reflect the code changes.

I've tested creating VMs with these changes on my ARM64 and x86_64 machines but don't have many devices to test against.

[stgraber]

@dustins have you had any luck with this one?

[dustins]

Yes, I actually am almost done just wanted to test on x86 and ARM64 before pushing. Sorry for the long delay! I think I can test tonight and then push up the changes for you to review.

[stgraber]

Sounds good.

We're releasing 6.2 today so that will most likely miss that release by a hair but it will be in 6.3 for sure.

[dustins]

I still have to test this on arm64/x86_64 to check that this all still works.

[dustins]

Ok I tested this on my x86_64/arm64 boxes and I was able to launch VMs with and without secure boot.

[stgraber]

Needless change caused by goimports.

[stgraber]

Looking good, just a few changes needed to get the tests to be happy!

[stgraber]

Looking at this one now

[stgraber]

I did:

• Fixed the missing sign-offs
• Rebased some commits together
• Fixed the import rename
• Ran make static-analysis and fixed what it picked up

[stgraber]

Done cleaning this one up and doing some testing on it.