Sonarcloud onboarding or removal

[SebastianBezold]

Description

Introduces with the a change in #64, the Sonar Cloud usage should be clarified.

The former value was matching a different Sonar Cloud project and is only available a specific fork.
Changing the value does not automatically create a new Sonar Cloud project.

This means a decision has to be made, if a proper Sonar Cloud onboarding will be done, or alternatively, we remove the related config + worklfows