OvmfPkg: IndustryStandard: add definitions from the VirtIo 1.0 spec

OvmfPkg: IndustryStandard: add definitions from the VirtIo 1.0 spec

These header files are intentionally minimal, and intentionally kept apart
from the VirtIo 0.9.5 headers.

The header inclusion chains end up like this (the Virtio10*.h header files
in the middle are new):

  Virtio.h    -> Virtio10.h    -> Virtio095.h

                     ^                 ^
                     |                 |

  VirtioNet.h -> Virtio10Net.h -> Virtio095Net.h

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Jordan Justen <jordan.l.justen@intel.com>