Implement 9P client support for libhvee

[cfergeau]

This is a follow-up for #3870

#3870 (comment)

However the guest part is more problematic, while podman can use mount -t 9p ... to mount the share because it's using fedora, this is not working in our microshift/openshift images because they are RHEL-based, and don't provide support for 9p out of the box. As 9p support is getting more complicated than expected, imo we should be moving forward with #3824 without 9p support, and work on it as a follow-up.

https://github.com/aperezdc/9pfuse could be an option of handling 9p in RHEL guests, there are probably other alternatives.
Or we can also conclude 9p is not a good option for us.