[torch_xla2] Simplify developer setup steps

[will-cromar]

• Add optional dependencies for CPU, CUDA, and TPU. Use jax[cuda12] instead of jax[cuda12_pip] since it doesn't require an extra index.
• Make use of global options in requirements.txts to install the CPU version of torch automatically.
• Use tensorflow-cpu because it's much smaller
• Recommend using VSCode to set up virtual env
• Update package dependencies
• Update name of test_requirements to match dev-requirements
• Add ruff tool setup and adjust to be more like yapf settings in main package. ruff check shows 42 errors, so we can start fixing these in future PRs.

Tested locally by deleting my old environment and creating a new one with these instructions.

[qihqi]

this is awesome. Thanks!