[ci] Deploy guix container to eve

• Builds and deploys a Apptainer/Singulary image on master pipelines to Eve at /data/ogs/apptainer/guix/ogs-petsc-ssd_head.squashfs
  • The build is done with GNU Guix and the resulting image features a portable OpenMPI implementation, i.e. hopefully it will run on other HPC platforms as well.
  • For Juwels users I manually copied the image to the project directory, please let me know if you try it (/p/project/ogs6hpc4/lars/mxh62396ylq1yn5dbgzh54d7lsqm9c3g-bash-ogs-petsc-squashfs-pack.gz.squashfs) --> does not work.
• A new CI job tests the image in a real cluster job submitted via sbatch (currently tests cube_1e3_XDMF_np3.prj), thanks to Toni H. from the Eve cluster team for the monitoring script!
• Added some docs on usage

1. Feature description was added to the changelog
2. Tests covering your feature were added?
3. Any new feature or behavior change was documented?