Add configuration options for search

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

**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 search entry point and the existing configuration handling; the issue names no files or tests. Confirm how library caching should apply, then verify that an enable_caching option defaults to false and that the requested production caching behavior is covered.

Written by the indexing model from the issue text.