Add a README to provide links to API providers

[carljparker]

What does this PR do?

Add a README.md to this directory that links to API providers that support Meta Llama.

Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• Did you read the contributor guideline,
  Pull Request section?
• Was this discussed/approved via a Github issue? Please add a link
  to it if that's the case.
• Did you make sure to update the documentation with your changes?
• Did you write any new necessary tests?

Thanks for contributing 🎉!

[HamidShojanazeri]

thanks @carljparker can we pls fix the spell check failures to merge.