Add `data` parameter to render_def

This adds the possibility to use Pyramid style context passing in render_def as
it has been allowed and recommended to do in render for a while.
Refactor badge index views
Split badge management in instance settings (finally fixes #665)
Add single badge type view
Add / fix some badge related format parameters
Add trivial current_url helper function
Add action urls to badge related forms

As the overlay related ajax_submit javascript code requires action
attributes in the respective forms, we add these, pointing to the
current URL.
Add badge management overlays in context
Always show badge related facets to admins
rm leftover template namespace
rm leftover active_subheader_nav
Merge pull request #713 from nidico/feature-split-badge-settings

Split badge management