Addresses https://git.xfel.eu/gitlab/detectors/pycalibration/merge_requests/464#note_228864

Fix/pre commit isort

See merge request detectors/pycalibration!434

Fix missed mixed line endings

We cannot rely on the directory creation date, as it might get modified with filesystem upgrades. File modification dates are conserved though (not creation date), so we must use these when the information is not available from run metadata