[tests.detect] Add basic dataset tests for detection module

tests/detect/__init__.py

...els/histograms_faster-rcnn[resnet50-v1]_cxr8_default.json

...els/histograms_faster-rcnn[resnet50-v1]_jsrt_default.json

...stograms_faster-rcnn[resnet50-v1]_montgomery_default.json

...histograms_faster-rcnn[resnet50-v1]_shenzhen_default.json

...ograms/raw_data/histograms_cxr8_preprocessed_default.json

...ect/data/histograms/raw_data/histograms_jsrt_default.json

...ta/histograms/raw_data/histograms_montgomery_default.json

...data/histograms/raw_data/histograms_shenzhen_default.json

tests/detect/test_cxr8.py

tests/detect/test_jsrt.py

tests/detect/test_montgomery.py

tests/detect/test_shenzhen.py