Caching and Etags for API calls

[dwaxe]

1. Install http://niwinz.github.io/django-redis/latest/ and set up Redis
2. Install https://django-extensions.readthedocs.io/en/latest/
3. Install http://chibisov.github.io/drf-extensions/docs/#cache-etag-mixins
4. Implement caching and etags and add tests
5. Implement Etag support (304 response code) on the Frontend

[quorth0n]

I've been meaning to log this, I also think varnish would be good to implement on top of nginx.

[dwaxe]

Thanks for the recommendation @whirish! I'm definitely not wedded to the implementation outlined in OP.