Optimize api for large datasets

**Feature request**
It would be great to have caching for parsers.

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

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

Start by locating the parser entry points and the existing configuration handling. Define how parser results are cached for large datasets, verify that enable_caching defaults to false, and add tests covering disabled and enabled behavior; done means the option works without changing the default path.

Written by the indexing model from the issue text.