Add scripts to export the encoder of Clay

[srmsoumya]

• [x] Add code to take the clay encoder & compile it to torch exported program format
• [x] Add code to compile torch encoder into onnx format
• [x] Notebook to show how to use the compiled models

Note: onnx gpu export is not implemented, will fix that in a new PR.

[srmsoumya]

@rbavery This PR adds compiled version of Clay v1 Encoder in ONNX & torch ExportedProgram format.

[lauracchen]

@srmsoumya We are still missing the onnx GPU export right? I'm only able to run onnx for some reason, so it'd be great to have access to the GPU version too (and I'm guessing maybe others might have the same experience)