Support module tarballs in QEMU deploys
In QEMU boot jobs, it's not possible to add a modules tarball to the deploy step.
Ideally, QEMU deploy should support the same artifacts as a TFTP deploy, and add the modules tarball to the rootfs/initram. This is especially useful as QEMU jobs need VIRTIO support which is not built into mainline x86 kernels by default, but could be built as a module and loaded at boot. This will also allow KernelCI to test modules on QEMU, as it currently does not.