Net Control Virtqueue shadow Support

Bugzilla: https://bugzilla.redhat.com/1939363 Upstream Status: git://git.qemu.org/qemu.git

Instruct Shadow Virtqueue about virtio-net control virtqueue commands, so it can update device model. It's an importante step to achieve live migration with vdpa net devices.

I need to backport some meson commits. If CentOS is never going to build without VIRTIO_NET, we can leave them out.

Other needed minor fixes backported too.