move templates to website/templates/

Note that we're still using the old, screwed-up manual calls to Jinja
to render these, so they still have an html extension and there's an
extra 'website' directory level. We still have to use the
FileSystemLoader to find them; Jinja doesn't provide an AppLoader like
Django or django-jinja do.
use django-jinja integration; rename templates; related changes

All the old views are still using HttpUtils, but it now uses the
correct django shortcuts and therefore uses the django-jinja
integration module. This greatly improves debugability and
extensibility, but it means renaming every template to use the .jinja
extension.

There were some minor tweaks to the template js blocks that I should
probably have put in a different commit, actually. Oh well.
Move the static files into website/static
Merge branch '89-move-templates' into devel