Browsable API

[stevelacey]

What does this PR do?

Adds a html ui when hitting endpoints in a web browser, which presents the output nicely for debugging, and means that Django can inject the debug toolbar.

Also drops worf's gzipmiddleware usage, apps can add that to their middleware stack if they want it, injecting it from within worf makes it difficult to order middlewares correctly so things like debug toolbar will work.

Based loosely on https://www.django-rest-framework.org/topics/browsable-api/

What issue does this solve?

I needed django debug toolbar.

Where should the reviewer start?

Hit up an api endpoint in Chrome.

Screenshots

What Worf gif best describes this PR or how it makes you feel?

Checklist

• This PR increases test coverage
• This PR includes README updates reflecting any new features/improvements to the framework
  • Template means that worf needs adding to INSTALLED_APPS
  • There's a couple of new settings for specifying api name/root url; though this could be done via overriding the template
• Might want to support an ?format=json or similar override