Unified training and evaluation via JSON files

In the folder `Experiments/configurations` JSON files are included that
contain the configuration for training and evaluating. All training
scripts were replaced by two files `train_eiv.py` and `train_noneiv.py`
that read from this folder. The hitherto existent training
configurations from the training scripts were copied to the JSON files.
For `yacht_hydrodynamics` the configuration was updated.
The script `evaluate_tabular.py` now also reads from this folder.