Packaging NEMU and virtiofsd starting with release 1.7

[sboeuf]

As discussed with the community in the context of supporting virtio-fs through Kata Containers, we will use NEMU as the test vehicle. Once NEMU will be rebased and patched with virtio-fs patches, it will include the feature we need to support virtio-fs from Kata.
We will need to include NEMU as part of the Kata Containers packages so that users can play with virtio-fs.
Also, the virtiofsd daemon binary should be generated by the NEMU project, and this should also be packaged by Kata Containers.

Summary being, we want both nemu and virtiofsd to be part of the release 1.7 packages.

[egernst]

Dependent on:
intel/nemu#206
intel/nemu#211