Add `data-set $dataSetId --terminate`

[BigLep]

Done Criteria

filecoin-pin data-set $dataSetId --terminate "terminates" a whole dataset, meaning both the dataset will be deleted and the rails will be terminated.

Why Important

Convenience cleanup and stop paying utility for users.

Notes

1. This relies on the work in Synapse at allow a client to terminate a service FilOzone/synapse-sdk#199
2. This was broken out of Add rm --piece $pieceCid command #8