Update lib documentation

**Feature request**
It would be great to have import for handlers.

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

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

Locate the handler registration and configuration parsing entry points, since no specific files or tests are named. Confirm how imports are currently handled, then implement the enable_import option with a default of false and verify that enabling it permits handler imports while the default preserves current behavior.

Written by the indexing model from the issue text.