Check the Sentry integration status

[DieterHolvoet]

Summary

Add a simple way to make sure the integration with Sentry is working as it should, without having to manually trigger exceptions and check the Sentry issue queue.

Motivation

Right now, the only way to test whether the integration with Sentry is setup right is to trigger an exception - or to wait until an exception is triggered on some page - and to check if a Sentry issue was created in the right project.