onnxruntime

Add onnx export script for segment anything v2 (#22119)

### Description
Add ONNX export script for segment anything v2 (SAM2).

### Limitations
* Does not support video. Only support image right now.
* The decoder does not support batch inference.

### Credits
The demo that is based on [SAM2
notebook](https://github.com/facebookresearch/segment-anything-2/blob/main/notebooks/image_predictor_example.ipynb),
and modified to run with ORT.

The export of decoder is inspired by
https://github.com/vietanhdev/samexporter.

### Demo
Example output of demo:

![sam2_demo](https://github.com/user-attachments/assets/9a9fa360-8c20-482e-9935-a7aba9cf15de)

### Motivation and Context
For support optimization of SAM2 image segmentation.