Refactor controllers for better readability

**Feature request**
It would be great to have caching for auth.

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

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

No files, tests, or entry points are named. Start by locating the authentication configuration and current auth flow, then determine where enable_caching belongs and how its default false value should behave. Done means the option is available and authentication caching works for the stated production use case.

Written by the indexing model from the issue text.