[experiment] Add iostar database

pyproject.toml

src/mednet/libs/segmentation/config/data/iostar/__init__.py

...mednet/libs/segmentation/config/data/iostar/datamodule.py

...dnet/libs/segmentation/config/data/iostar/optic-disc.json

...mednet/libs/segmentation/config/data/iostar/optic_disc.py

src/mednet/libs/segmentation/config/data/iostar/vessel.json

src/mednet/libs/segmentation/config/data/iostar/vessel.py

...ata/histograms/models/histograms_lwnet_iostar_vessel.json

...ts/data/histograms/raw_data/histograms_iostar_vessel.json

src/mednet/libs/segmentation/tests/test_iostar.py