[common] (datasets) refactor: drop previous system

common/research/common/dataset/improvement/zoom.py

common/research/common/dataset/tensorflow_record.py

common/research/common/datasets/__init__.py

common/research/common/datasets/capped_dataset.py

common/research/common/datasets/dataset.py

common/research/common/datasets/dataset_builder.py

common/research/common/datasets/filter_dataset.py

common/research/common/datasets/image_dataset.py

...on/research/common/datasets/image_file_dataset_builder.py

common/research/common/datasets/iterator_dataset.py

common/research/common/datasets/lazy_dataset.py

common/research/common/datasets/roco/__init__.py

common/research/common/datasets/roco/roco_annotation.py

common/research/common/datasets/roco/roco_dataset.py

common/research/common/datasets/roco/roco_dataset_builder.py

.../research/common/datasets/roco/roco_dataset_descriptor.py

common/research/common/datasets/roco/roco_datasets.py

common/research/common/datasets/roco/zoo/__init__.py

common/research/common/datasets/roco/zoo/dji.py

common/research/common/datasets/roco/zoo/dji_zoomed.py