redo theme support in a non-dumb way

Man. what was I thinking? Discovered django had a really easy way to do this with TEMPLATE_DIRS, so I did that.

Now we can override ANY template, not just the ones in themed/ and/or static_views/ dir.

example:  templates_themed/preregistration/disclaimers.html overrides th same file in templates/preregistration

so:
- renamed themed/ back to static_view/
- created a new dir named templates_themed/
- setup configspec.ini to setup TEMPLATES_DIR