default storage class

[afrikha]

For charmed k8s on openstack you need to specify the default storage class otherwise the jupyter notebook cannot instantiate new volume:

kubectl patch storageclass cdk-cinder -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}'

[Bartłomiej Poniecki-Klotz]

Thanks a lot! Commit with documentation addition is already in the main.
1ab7a43