[cwconfig] make appobjects_cubes_modnames() public
The method is used in cubicweb.cwvreg without underscore and outside of the
config class, so let's make this method public.
Fix autoreload with twisted.
Upstream Author:
%(author)s <%(author-email)s>
Copyright:
Copyright (c) %(year)s %(author)s.
%(author-web-site)s -- mailto:%(author-email)s