Optimize controllers for large datasets

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

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

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

Search the repository for the existing authentication configuration and any import-related handling; the issue does not name a file or test. Confirm how configuration defaults are defined, add the requested disabled-by-default option, and verify that authentication import behavior is covered without affecting existing deployments.

Written by the indexing model from the issue text.