Refactoring templates to each app.

Title says it all.  Templates stay inside `{app}/templates/{app}` directory in order to avoid potential future template naming collisions.  

`TEMPLATE_DIRS` is defined within each app's `settings.py` to include just that app's template directory, then constructed globally from `INSTALLED_APPS` with the existing project `settings.py` recombination code, validating that the `settings.py` separation is a really nice method for app encapsulation.

Testing:
* Clicked on URLs/views for each app, to validate that rendering seems right.  Did this for most `distributed` views, since those had actual code tweaks (to pre-pend `distributed` to the template names)