allow long badge descriptions
add category image

Conflicts:
	src/adhocracy/config/routing.py
	src/adhocracy/controllers/category.py
add config ui for category image

Conflicts:
	src/adhocracy/controllers/badge.py
allow to set proposal category in query on new
add parameter extra_filter to solr_proposal_pager
add parameter visible_only to model.badge.all
add category tab to instance navigation
create category views
only show leaves in category index
use pages_pager in category sidebar