Purpose

default the podman/buildah/skopeo storage driver to VFS because iss what works in rootless mode.

NOTE: brand new kernels can support rootless overlay but it isn't wide spread enough yet to be useful, but when it is can be overriden with env var and the default can be changed when it makes sense

This also fixes bug where needed the podman socket in jkube to be set to the same storage driver as the podman commands run in other steps which are currently hard coded to vfs.