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.
Edited by Florian Uhlig