add licensing headers

nifty5/domains/log_rg_space.py

nifty5/energies/kl.py

nifty5/library/amplitude_model.py

nifty5/library/apply_data.py

nifty5/library/correlated_fields.py

nifty5/library/point_sources.py

nifty5/multi/block_diagonal_operator.py

nifty5/multi/multi_domain.py

nifty5/operators/domain_distributor.py

nifty5/operators/exp_transform.py

nifty5/operators/qht_operator.py

nifty5/operators/slope_operator.py

nifty5/operators/symmetrizing_operator.py