Add Detectron2 model support to accuracy checker

[pwolnows]

Summary

Adds Detectron2 model support to the PyTorch launcher and accuracy checker adapters, hardens dataset reading against transient OS-level I/O errors, and includes a handful of related fixes and dependency updates picked up along the way.

Detectron2 Support

• Added Detectron2Adapter (accuracy_checker/adapters/detectron2.py) to convert Detectron2 Instances-based output into DetectionPrediction/InstanceSegmentationPrediction representations, with 0-based class indexing.
• Added Detectron2Wrapper (accuracy_checker/launcher/detectron2_wrapper.py), a compatibility adapter that:
  • converts batched tensor input into the [{"image": tensor}, ...] dict format expected by Detectron2 models;
  • extracts pred_boxes, pred_classes, pred_masks, and scores from the returned Instances objects;
  • loads checkpoints that contain a fully constructed model object directly, without invoking the model constructor.
• PyTorchLauncher gains a use_detectron2_wrapper config flag that delegates model preparation and checkpoint loading to Detectron2Wrapper, keeping Detectron2-specific logic out of the generic launcher code path.
• Documented the new parameter and wrapper behavior in pytorch_launcher_readme.md, including a sample config.

Retry on Transient Read Errors

• BaseReader now retries reads that fail with a transient OSError (e.g. flaky network shares), instead of failing the whole dataset validation run.
• New optional reader parameters:
  • read_retry_attempts (default 1, i.e. no retry)
  • read_retry_delay (default 0.1 seconds)
• Documented in data_readers/README.md with a config example.
• Added regression test TestBaseReaderRetry::test_retry_transient_read_error covering the retry-then-succeed path.

Dataset & Evaluator Fixes

• Fixed annotation saving so converted annotations are always stored for the full dataset, not just the subsample size, when sub_evaluation is combined with subset settings.

Testing

• tests/test_config_validator.py::TestBaseReaderRetry::test_retry_transient_read_error — verified passing.