Replace SonarCloud GitHub action

Our SonarCloud pipeline has been failing since Friday afternoon. At first, I thought this may be a rate limit we are hitting, but looking into it a bit further, we see the following errors:

Secret source: Actions
Prepare workflow directory
Prepare all required actions
Getting action download info
Error: Unable to resolve action sonarsource/sonarcloud-github-c-cpp, repository not found

See e.g. this job.

The repository of the sonarcloud-github-c-cpp GitHub action is not available anymore. It seems that project is archived (although I don't see why the entire repo is unavailable). Following this post, we should replace this with the sonarqube-scan-action which apparently now has built-in support for C/C++: