Look into Kata Containers for GitLab runners

We can't easily build arch-boxes in a safe way. We need access to either a loop device (which isn't safe) or use libguestfs (require FUSE + unprivileged user namespaces + qemu).

Either solutions is messy. It would be easier if could run docker with --privileged and be done with it. Kata Containers could probably allow us to do that.