async views/streaming responses

[jclgoodwin]

• Use a server other than gunicorn, that supports asgi
  • Deploy to a test environment first
• Django and its template engine doesn't properly support streaming templates yet, but there's a slightly verbose way of doing it using Jinja so let's try that. The service detail view would benefit from it
  • (but a smaller simpler view would be easier to start with, given the need to convert the template to Jinja)