Add models for store Milestone, Maintainer and Recipe{Maintainer,
Upgrade, Upstream, Distro}, add initial data for Milestone and
Maintainer, initial migration and admin sites.
Add rrs/context_processors.py for return the site_name and application
for use in templates.
Signed-off-by: Aníbal Limón <anibal.limon@linux.intel.com>
