File sharing

[kimfaint]

Adds the ability to share a directory on the Linux host with the Windows guest using the incus config device add command.

Sourced from https://blog.simos.info/how-to-run-a-windows-virtual-machine-on-incus-on-linux/#bonus-material-4-how-to-mount-a-directory-from-the-host-to-the-windows-vm

[antifob]

This one's nice, but I'll put it on hold.

I have no position on VirtioFS because I haven't tried it yet. However, I had echoes that it is unreliable. I'll let it sit for a while until I have time to try it.

@kimfaint Please, let me know if you encounter any issues with it as others seem to have experienced.

[kimfaint]

@antifob I will be using the file sharing quite a bit over the next few months.

I'm using these tools awesome tools of yours to spin up Windows VMs to run automated tests of our Windows software. The tests run from the Incus host and in order to get the test files onto the VM guest I will just share the repo directory of the Linux host with the Windows guest. Then once the tests run the Windows VM is shutdown and deleted, but all the test logs and other output files including a video capture are right there in the repo on the Linux host.

I'll report back how reliable I find VirtioFs it to be.