Extend TimerProvider

My use case arises from reasons of privacy and right to erasure. Similar to this topic I want to run three regularly scheduled tasks to delete accounts.
Running such tasks at least once per day would be enough, but even this could fail if the interval is too and K8s restarts Keycloak. So it would be easier to configure a short delay instead of running the task multiple times per day. It is easier for testing, too.