Add endpoint for monitoring

[VolkerHartmann]

Is your feature request related to a problem? Please describe.
For service monitoring, it is helpful to have a separate endpoint that can display all relevant data.

Describe the solution you'd like
The endpoint should be accessible via the /actuator path.

Describe alternatives you've considered
Optionally there should be one or more of the following possibilities to make endpoint accessible

• for authenticated users only
• for admins only
• for specific role only
• only from localhost

[github-actions]

Branch issue-725-Add_endpoint_for_monitoring created!