Provide an more sane way to get usage information for a particular
project's quotas. This requires using the 'Lister' command type since
the 'ShowOne' command type only allows for simple key-value pair output.
We also add a note indicating that the '<project>' argument is optional.
Change-Id: Ic7342cf08f024cc690049414c5eef5b9a7594677
Signed-off-by: Stephen Finucane <sfinucan@redhat.com>
04e68e0d5a