test: replace Tap interfaces in test setup

[fstreun]

In the virtualized setup for the integration tests (test/testnet_ip/, test/testnet_scion/), LF uses Tap interfaces:

		--vdev=net_tap0,remote=... \
		--vdev=net_tap1,remote=... \

The DPDK Tap interfaces have the limitation that "Rx/Tx must have the same number of queues" (see here).
This limitation may hinder future development. Hence, we should replace them with a suitable alternative that does not have that limitation.

As an alternative, we could use the virtual device virtio-user. Checkout following sources:

• http://doc.dpdk.org/guides-22.11/howto/virtio_user_for_container_networking.html
• http://doc.dpdk.org/guides-22.11/howto/virtio_user_as_exception_path.html

Note:
Verify that the devices also work in the CI.