Add configuration options for backup

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

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

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

No file, entry point, or test is named in the issue. Start by locating configuration parsing and the existing model backup or export flow, then determine how enable_export should control it. Done should include the new option defaulting to false, documented behavior, and tests covering the disabled and enabled cases.

Written by the indexing model from the issue text.