Remove/hide wipe command

[tillrohrmann]

The wipe command makes it a tad bit too easy to delete one's data. Moreover, with #1317 there should no longer be the need for wiping one's data directory. That's why we could think about removing/hiding the wipe command to train our users in better practices. There is still the escape hatch of manually deleting the restate-data or any of the sub-directories.