Some refactoring

.../low_level_cut_study/fsp_low_level_cuts_batch_config.json

...figs/low_level_cut_study/low_level_cuts_batch_config.json

...el_cut_study/configs/fsp_low_level_cuts_batch_config.json

...low_level_cut_study/configs/low_level_cut_study_conf.yaml

..._level_cut_study/configs/low_level_cuts_batch_config.json

rdstar/studies/low_level_cut_study/low_level_cut_study.py

...ar/studies/low_level_cut_study/reconstruction/__init__.py

.../reconstruction/reconstruction_fsp_low_level_cut_study.py

...tudy/reconstruction/reconstruction_low_level_cut_study.py

rdstar/studies/low_level_cut_study/utilities/__init__.py

...low_level_cut_study/utilities/decay_channels_cut_study.py

...el_cut_study/utilities/final_state_particles_cut_study.py

...low_level_cut_study/utilities/low_level_cut_defintions.py

rdstar/studies/low_level_cut_study/utilities/plotting.py

rdstar/studies/low_level_cut_study/utilities/utilities.py