ReactOS gets support for UEFI booting

After several months of (public) work, ReactOS can now use UEFI boot.

But that's the major changes planned for this PR. As of the state of this PR UEFI boot will operate as long as you have a serial port you should be able to test it.

Some more boot fixes will come down the road but this covers 85% of devices we've ran into.

In fact, they've even made it possible for ReactOS to boot on the Steam Deck, which is surely a neat trick. I'm sure once this has been polished up a bit more - if that's even necessary - it will make its way to the next ReactOS release.