Optimize store for large datasets

**Description**
Currently data lacks proper import support.

**Proposed solution**
Add configurable import with sensible defaults.

**Priority**: Low/Medium

No file, test, or entry point is named. Start by locating the current data store and any existing import path, then determine how configurable imports and their defaults should be represented. Done means large datasets can be imported with documented, sensible defaults, verified by the relevant import tests.

Written by the indexing model from the issue text.