kind: allow recursive mounts of the single files in /etc by pods in k8s
Previous to this change, containerd inside kind (docker) would fail to mount individual files inside the kind container.
The new propagation setting helps with this, see upstream docs: https://kubernetes.io/docs/concepts/storage/volumes/#mount-propagation
Signed-off-by: Arturo Borrero Gonzalez aborrero@wikimedia.org