Make platform nfs-provisioner the cluster NFS provisioner

Within NXBT-3515, we've deployed a nfs-provisioner in the platform namespace.

We still have a nfs-server in the nfs-server namespace that was used originally by the NOS team, but it is not the case anymore.

We've started to cleanup k8s objects within NXBT-3733, we can also cleanup this former nfs-server and make our provisioner a cluster wide service, such as we've done for cert-manager.
This is about deploying our provisionner in a dedicated namespace and removing the platform- prefix + deleting the other objects related to the previous provisioner.