Prepare a subsection to educate users on the PyTorch workloads on AI-Hypercomputer

[miladm]

📚 Documentation

AI-Hypercomputer is where customers and users can find optimized implementation of representative models.

Please add a section in the PyTorchXLA README page (and the html documentation) that introduces this concept and points the users to the following resource: https://github.com/AI-Hypercomputer/tpu-recipes

Keep in mind that the AI-Hypercomputer tpu-recipe repo is WIP and gradually grows in scope.

Read more context on AI-Hypercomputer

Timeline: would be great to add this documentation to the repo for 2.6 branch cut.

cc @tengyifei

[mikegre-google]

Fixed with PR: 8412