Allow for sending a local volume name that differs from the remote volume name

[recunius]

I have the need to store a different remote volume name from the one which exists locally. In my case this is because I have multiple source machines with slightly different zfs pool+filesystem layouts even though the filesystems are logically the same.

Does it make sense to allow a --localVolume VOLUME option so a user can specify a different local volume?

If so, I have a PR for review.

[someone1]

Can you say more about why this would be useful? Do you want to backup from the multiple source machines at once under the same logical volume name? It's not clear that this is a safe mode of operation