[models] Improve documentation of config files; Make ptbench config work again

...bench/data/montgomery_shenzhen_indian_tbx11k/v2_fold_6.py

...bench/data/montgomery_shenzhen_indian_tbx11k/v2_fold_7.py

...bench/data/montgomery_shenzhen_indian_tbx11k/v2_fold_8.py

...bench/data/montgomery_shenzhen_indian_tbx11k/v2_fold_9.py

...ata/montgomery_shenzhen_indian_tbx11k/v2_others_vs_atb.py

src/ptbench/data/nih_cxr14/cardiomegaly.py

src/ptbench/data/nih_cxr14/datamodule.py

src/ptbench/data/nih_cxr14/default.py

src/ptbench/data/nih_cxr14_padchest/idiap.py

src/ptbench/data/padchest/cardiomegaly_idiap.py

src/ptbench/data/padchest/datamodule.py

src/ptbench/data/padchest/idiap.py

src/ptbench/data/padchest/no_tb_idiap.py

src/ptbench/data/padchest/tb_idiap.py

src/ptbench/data/shenzhen/datamodule.py

src/ptbench/data/shenzhen/default.py

src/ptbench/data/shenzhen/fold_0.py

src/ptbench/data/shenzhen/fold_1.py

src/ptbench/data/shenzhen/fold_2.py

src/ptbench/data/shenzhen/fold_3.py