Move NetQueuePair and the related NetCounters into the net_util crate.
This means that the vhost_user_net crate now no longer depends on
virtio-devices and so does not depend on the pci, qcow or other similar
crates. This significantly simplifies the build chain for this backend.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
By moving the code for opening the two RX and TX queues into a shared
location we are starting to remove the requirement for the
vhost-user-net backend to depend on the virtio-devices crate which in of
itself depends on many other crates that are not necessary for the
backend to function.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
