cli/setup: Add sanity check for the --mode switch when creating the config directory
cli/setup: Do not translate \n
cli/setup: Issue an error if chmod fails when setting up the configuration directory
cli/setup: Do not return false; after $this->fail()

$this-fail() throws an exception.
cli/setup: Do not translate \n again
cli/setup: Do not exit setup config directory when the directory already exists

mkdir may succeed but chmod or chgrp may fail. The next time the command is called
it will ll exit before trying to chmod or chgrp again because the directory already exists.
cli/setup: Issue nice error messages when creating the config directory fails