[doc] Add segmentation configs in documentation

doc/api.rst

doc/config.rst

doc/install.rst

doc/links.rst

doc/references.rst

src/mednet/libs/segmentation/config/data/cxr8/default.py

src/mednet/libs/segmentation/config/data/drionsdb/expert1.py

src/mednet/libs/segmentation/config/data/drionsdb/expert2.py

...et/libs/segmentation/config/data/drishtigs1/datamodule.py

...libs/segmentation/config/data/drishtigs1/optic_cup_all.py

...libs/segmentation/config/data/drishtigs1/optic_cup_any.py

...ibs/segmentation/config/data/drishtigs1/optic_disc_all.py

...ibs/segmentation/config/data/drishtigs1/optic_disc_any.py

src/mednet/libs/segmentation/config/data/drive/default.py

src/mednet/libs/segmentation/config/data/drive/drive_2nd.py

src/mednet/libs/segmentation/config/data/hrf/default.py

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

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

src/mednet/libs/segmentation/config/data/jsrt/datamodule.py

src/mednet/libs/segmentation/config/data/jsrt/default.py