This changes the workflow for destroying a husk slightly. Rather than
`coco husk destroy` actually removing the husk and its associated config
information, `coco husk destroy` just destroys the resources. Then,
afterwards, to permanently remove the husk, you use `coco husk rm`.
As usual with `rm`-style commands, it refues to remove the husk if there
are any resources still associated with it; however, `--force` overrides
this default.