[mednet.tests] Move tests to single directory

tests/classification/data/lfs/models/logreg.ckpt

tests/classification/data/lfs/models/signstotb.ckpt

tests/classification/data/mednet.toml

tests/classification/data/test_predictions.csv

tests/classification/data/test_vis_metrics.csv

tests/classification/test_cli_classification.py

tests/classification/test_evaluator.py

tests/classification/test_hivtb.py

tests/classification/test_indian.py

tests/classification/test_montgomery.py

tests/classification/test_montgomery_shenzhen.py

tests/classification/test_montgomery_shenzhen_indian.py

...lassification/test_montgomery_shenzhen_indian_padchest.py

.../classification/test_montgomery_shenzhen_indian_tbx11k.py

tests/classification/test_nih_cxr14.py

tests/classification/test_nih_cxr14_padchest.py

tests/classification/test_padchest.py

tests/classification/test_saliencymap_interpretability.py

tests/classification/test_shenzhen.py

tests/classification/test_summary.py