Make the new released CTAO spectrum package (https://pypi.org/project/ctao-dpps-cosmic-ray-spectra/) as a dependency in pyirf and get rid of the `pyirf/spectral.py` here in order to avoid duplication.
Make the new released CTAO spectrum package (https://pypi.org/project/ctao-dpps-cosmic-ray-spectra/) as a dependency in pyirf and get rid of the
pyirf/spectral.pyhere in order to avoid duplication.