[classify] Change sample data to a dict, use v2 transforms

src/mednet/classify/config/data/hivtb/datamodule.py

src/mednet/classify/config/data/montgomery/datamodule.py

src/mednet/classify/config/data/nih_cxr14/datamodule.py

src/mednet/classify/config/data/padchest/datamodule.py

src/mednet/classify/config/data/shenzhen/datamodule.py

src/mednet/classify/config/data/tbpoc/datamodule.py

src/mednet/classify/config/data/visceral/datamodule.py

src/mednet/classify/config/models/alexnet.py

src/mednet/classify/config/models/alexnet_pretrained.py

src/mednet/classify/config/models/densenet.py

src/mednet/classify/config/models/densenet_pretrained.py

src/mednet/classify/config/models/densenet_rs.py

src/mednet/classify/config/models/pasa.py

src/mednet/classify/models/classification_model.py

src/mednet/classify/models/normalizer.py

src/mednet/data/datamodule.py

src/mednet/data/typing.py

src/mednet/models/transforms.py