Add test for Debian12 using Apptainer
Use the Apptainer runner to test CbmRoot on a Debian12 container. Debian12 (bookworm) will be released mid of June.
This MR contains two changes. First it add a test for Debian12. Instead of using Singularity as container runtime the successor Apptainer is used. In future more and more of the test will be moved from Singularity to Apptainer.