Clean up gunicorn logging

In production, we're getting a lot of useless noise like this in our Logentries app:

I'd like our logs to be more relevant so we can see what's actually going on in our apps. Getting rid of those gunicorn logs that we never use would be a good start.

Start by locating the Gunicorn logging configuration used by the production application and compare its output with the noise shown in the issue. Confirm which messages are unnecessary while preserving logs needed to understand application behavior; done means the unwanted Gunicorn entries no longer appear in production logs.

Written by the indexing model from the issue text.