Update parsers documentation

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

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

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

No file, test, or entry point is named. Start by locating the parser configuration and model-import paths, then determine where `enable_import` should be documented and applied; done means the option defaults to false and enables model imports when set true.

Written by the indexing model from the issue text.