…-layer into 2023.06-software.eessi.io-cuDNN-8.9.2.26-system

- `EESSI-install-software.sh`
  - use `scripts/gpu_support/nvidia/install_cuda_and_libraries.sh` with
    `scripts/gpu_support/nvidia/eessi-2023.06-cuda-and-libraries.yml`
- `create_lmodsitepackage.py`
  - consolidate `eessi_{cuda,cudnn}_enabled_load_hook` functions in a single one
    (`eessi_cuda_and_libraries_enabled_load_hook`)
  - the remaining hook is prepared to easily add new modules, e.g., cuTENSOR
- `eb_hooks.py`
  - put code that iterates over all files replacing non-distributable ones with
    symlinks into `host_injections` with a common function
    (`replace_non_distributable_files_with_symlinks`)
- `install_scripts.sh`
  - add files to copy to CVMFS (see `nvidia_files`)
- `scripts/gpu_support/nvidia/install_cuda_and_libraries.sh`
  - improved creation of tmp directory