Missing file delete, directory delete and directory empty

For our deployment scenarios, we run into dynamically named files that never would be overwritten and in those cases we could benefit from having commands like:

dw files --emptydir folder
or the /admin/api/DirectoryEmpty

dw files --deletedir folder
or the /admin/api/DirectoryDelete

dw files --deletefile file
So that it would invoke the /admin/api/FileDelete 
