Set up logging of some kind

## Description

It would be nice to have visibility of metrics such as:
1. # of harmonisations in a given week/day/hour

maybe we can do this with front end analytics

## Rationale

so we can see how many people are using the tool and if this is increasing over time

The issue names no files, tests, or entry points. First identify the API entry point for harmonisations and decide how daily, weekly, and hourly usage counts should be recorded; done means those metrics can be viewed over time to measure tool usage.

Vom Indexierungsmodell aus dem Issue-Text verfasst.