added folds for tbx11k split3

src/ptbench/configs/datasets/tbx11k_simplified/fold_0.py

src/ptbench/configs/datasets/tbx11k_simplified/fold_0_rgb.py

src/ptbench/configs/datasets/tbx11k_simplified/fold_1.py

src/ptbench/configs/datasets/tbx11k_simplified/fold_1_rgb.py

src/ptbench/configs/datasets/tbx11k_simplified/fold_2.py

src/ptbench/configs/datasets/tbx11k_simplified/fold_2_rgb.py

src/ptbench/configs/datasets/tbx11k_simplified/fold_3.py

src/ptbench/configs/datasets/tbx11k_simplified/fold_3_rgb.py

src/ptbench/configs/datasets/tbx11k_simplified/fold_4.py

src/ptbench/configs/datasets/tbx11k_simplified/fold_4_rgb.py

src/ptbench/configs/datasets/tbx11k_simplified/fold_5.py

src/ptbench/configs/datasets/tbx11k_simplified/fold_5_rgb.py

src/ptbench/configs/datasets/tbx11k_simplified/fold_6.py

src/ptbench/configs/datasets/tbx11k_simplified/fold_6_rgb.py

src/ptbench/configs/datasets/tbx11k_simplified/fold_7.py

src/ptbench/configs/datasets/tbx11k_simplified/fold_7_rgb.py

src/ptbench/configs/datasets/tbx11k_simplified/fold_8.py

src/ptbench/configs/datasets/tbx11k_simplified/fold_8_rgb.py

src/ptbench/configs/datasets/tbx11k_simplified/fold_9.py

src/ptbench/configs/datasets/tbx11k_simplified/fold_9_rgb.py