Resolve "switch Sibyll to C7 decay configuration"

applications/c8_air_shower.cpp

corsika/detail/modules/sibyll/HadronInteractionModel.inl

corsika/detail/modules/sibyll/InteractionModel.inl

corsika/modules/Sibyll.hpp

corsika/modules/sibyll/HadronInteractionModel.hpp

corsika/modules/sibyll/InteractionModel.hpp

examples/cascade_examples/em_shower.cpp

examples/cascade_examples/mars.cpp

examples/cascade_examples/mc_conex.cpp

examples/cascade_examples/radio_em_shower.cpp

examples/cascade_examples/water.cpp

modules/sibyll/sibyll2.3d.hpp

tests/modules/testCONEX.cpp

tests/modules/testSibyll.cpp