[models] Add support for learning rate schedulers

src/mednet/libs/segmentation/models/driu.py

src/mednet/libs/segmentation/models/driu_bn.py

src/mednet/libs/segmentation/models/driu_od.py

src/mednet/libs/segmentation/models/driu_pix.py

src/mednet/libs/segmentation/models/hed.py

src/mednet/libs/segmentation/models/lwnet.py

src/mednet/libs/segmentation/models/m2unet.py

src/mednet/libs/segmentation/models/segmentation_model.py

src/mednet/libs/segmentation/models/unet.py