Support syncing PersistentVolumes to the host cluster

[siredmar]

Currently it does not work to create a PersistentVolume within a vcluster. Allow creating PersistentVolumes within the vcluster and sync them back to the host cluster just like the sync-node-changes parameter.

[FabianKramm]

@siredmar thanks for creating this issue! As discussed in slack, we could add an option to sync persistent volumes from the vcluster to the host cluster.

[matskiv]

This was implemented in #116