Support ingesting PyTorch models

[pcolange]

This Issue is a feature request for the ability to load PyTorch models from a *.pth file into the GUI. Natively supporting PyTorch would require a new model summary GUI page, so we opt for this first pass to export PyTorch models as ONNX models so we can leverage all the current capabilities without requiring new PyTorch capabilities.

The story for this feature will include these steps:

1. Enable *.pth files to be opened into Digest AI
2. Open a new ingest window to enable users to set input dtypes and shapes and configure other export options
3. Export the PyTorch model as an ONNX model
4. Load exported ONNX model into Digest using the already supported ONNX model path