Support logging configuration

**Feature request**
It would be great to have notifications for middleware.

**Use case**
Many users need this functionality for production deployments.

**Implementation idea**
Add a new config option `enable_notifications` with default `false`.

No files, tests, or entry points are named. Start by locating the existing middleware and configuration handling, then determine how notifications are expected to work in production deployments. Done should include a recognized enable_notifications option with a default of false, but the notification behavior itself needs clarification.

Written by the indexing model from the issue text.