[django] Load templates with django.template.loaders.cached.Loader

Created by: nemesisdesign

A small optimization that's easy to add: https://docs.djangoproject.com/en/1.10/ref/templates/api/#django.template.loaders.cached.Loader

But we need to activate the django cache with django redis with these two:

• http://niwinz.github.io/django-redis/latest/#_configure_as_cache_backend
• http://niwinz.github.io/django-redis/latest/#_configure_as_session_backend