Add hints on starting nfs server

[Anders Björklund]

Explain how to set up an nfs server on the control plane:

https://wiki.gentoo.org/wiki/Nfs-utils

And how to use this server to create persistent volumes:

https://kubernetes.io/docs/concepts/storage/volumes/#nfs

[Anders Björklund]

Eventually this should also include a deployment of CSI:

• https://github.com/kubernetes-csi/csi-driver-nfs

https://github.com/kubernetes-csi/csi-driver-nfs/tree/master/deploy

kubectl apply -f $repo/rbac-csi-nfs-controller.yaml
kubectl apply -f $repo/csi-nfs-driverinfo.yaml
kubectl apply -f $repo/csi-nfs-controller.yaml
kubectl apply -f $repo/csi-nfs-node.yaml