autodocument commands from plugins using stevedore.sphinxext
autodocument commands from plugins using stevedore.sphinxext

conflicting command names are a painpoint, so is manually updating
a list. let's autodocument the commands that are being use by
existing osc supporters.

Change-Id: If37d81dfd57cc79803668b64be1ccd776e319572

dtroyer/osc-lib