Merge branch 'lukas_issue306_feat_data-handler-fir-filter' into 'develop'

conftest.py

mlair/configuration/defaults.py

mlair/data_handler/abstract_data_handler.py

mlair/data_handler/data_handler_kz_filter.py

mlair/data_handler/data_handler_mixed_sampling.py

mlair/data_handler/data_handler_single_station.py

mlair/data_handler/data_handler_with_filter.py

mlair/data_handler/default_data_handler.py

mlair/helpers/filter.py

mlair/helpers/helpers.py

mlair/helpers/statistics.py

mlair/model_modules/fully_connected_networks.py

mlair/model_modules/loss.py

mlair/model_modules/recurrent_networks.py

mlair/plotting/data_insight_plotting.py

mlair/run_modules/experiment_setup.py

mlair/run_modules/post_processing.py

mlair/run_modules/pre_processing.py

test/test_configuration/test_defaults.py

test/test_data_handler/test_data_handler_mixed_sampling.py