Create Praefect commands to list virtual storages and storages
Without dissecting the Praefect configuration, it is hard to tell for an admin what virtual storages and storages there are. This results in confusion which parameters are expected by commands when it says e.g.
<virtual-storage>. It would probably help by quite a lot if we had commands which explicitly list only this information. E.g.
$ praefect -config /path/to/config list-virtual-storages vs1 vs2 $ praefect -config /path/to/config list-storages -virtual-storage vs1 storage-1 storage-2 storage-3