Generalize PyTorch Custom Operatiors documentation

[ashokei]

📚 The doc issue

Based on the feedback received in a PR for sycl custom op documention, we were requested to open a documentation issue to track and generalize the pytorch custom op documention first.

https://docs.pytorch.org/tutorials/advanced/custom_ops_landing_page.html

Currently, the above doc is CUDA specific, we need to generalize it and add sub-page as needed for specific backend impl. Please share any comments or feedback.

Suggest a potential alternative/fix

No response

cc @svekars @sekyondaMeta @AlannaBurke

[malfet]

@albanD do you think this should be in PT or tutorials repo? (Moving to tutorials for now)

[albanD]

I think there are 3 things to balance here:

• Leverage sharing whenever possible. Any document that works for either backend can drop any mention of any backend.
• Consider user first: sometimes, having everything in one page is not the best as it makes it very hard to go through. We shouldn't hesitate to split things into multiple pages / tutorials as needed to ensure clear separation.
• Maintaining these pieces is non trivial. And so we need to ensure that the people maintaining these piece are comfortable with the extra workload of supporting SYCL. If not, it is fair to have a separate piece only about SYCL that is maintained by different people.