Add rate limiting for retry

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

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

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

The title requests rate limiting for retry, while the body requests config import and an `enable_import` option; clarify the intended scope first. No files, tests, or entry points are named, so locate the configuration-loading path and define the expected import behavior before implementation.

Written by the indexing model from the issue text.