Vhost-user-net has a dependency on address space from `MmioV2DeviceState`.
The addition of the address space is introduced in this patch. Plus, it
makes sure all unit tests have the according parameter as well.

Fixes: kata-containers#8502

Signed-off-by: Xuewei Niu <niuxuewei.nxw@antgroup.com>

This PR introduces vhost-user-net devices to Dragonball. The devices are
allowed to run as server on the VMM side.

Fixes: kata-containers#8502

Signed-off-by: Eric Ren <renzhen@linux.alibaba.com>
Signed-off-by: Liu Jiang <gerry@linux.alibaba.com>
Signed-off-by: Zha Bin <zhabin@linux.alibaba.com>
Signed-off-by: Chao Wu <chaowu@linux.alibaba.com>
Signed-off-by: Zizheng Bian <zizheng.bian@linux.alibaba.com>
Signed-off-by: Xuewei Niu <niuxuewei.nxw@antgroup.com>

Config space of network device is shared and accord with virtio 1.1 spec.
It is a good way to abstract the common part into one function.
`set_config_space()` implements this.

Plus, this patch removes `vq_pairs` from vhost-net devices, since there is
a possibility of data inconsistency. For example, some places read that
from `self.vq_pairs`, others read from `queue_sizes.len() / 2`.

Signed-off-by: Xuewei Niu <niuxuewei.nxw@antgroup.com>