Add a new --rootless-cni option to podman unshare to also join the
rootless-cni network namespace. This is useful if you want to connect
to a rootless container via IP address. This is only possible from the
rootless-cni namespace and not from the host namespace. This option also
helps to debug problems in the rootless-cni namespace.
Signed-off-by: Paul Holzinger <paul.holzinger@web.de>