Add configuration options for notifications

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

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

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

The issue names no files, tests, or entry points. Start by locating the configuration handling and store implementation, then determine how a new enable_caching option would affect them. Done means the option defaults to false and the requested store caching behavior is covered by suitable tests.

Written by the indexing model from the issue text.