Update controllers documentation

**Feature request**
It would be great to have filtering for components.

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

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

Start with the controllers documentation and locate the configuration entry point for component selection. Confirm the intended filtering behavior and affected components with maintainers; done means the `enable_filtering` option is documented, defaults to `false`, and the agreed filtering behavior is covered by appropriate tests.

Written by the indexing model from the issue text.