Show build number

[bonndan]

As a user I need to see the build number to report issues properly.

• [] read git commit id: https://doc.akka.io/docs/akka-management/current/kubernetes-deployment/building-using-maven.html#building-using-maven
• show in API root: store version and commit id in application.yml -> https://www.baeldung.com/spring-boot-build-properties#yaml
• show in frontend
• show in manual if possible (see if index.rst can be modified with placeholders like application.yml)

[bonndan]

Using a dynamic build number with Sphinx/rst is not possible in the scope of this ticket. It would require too much effort if possible at all.