Getting started notebook update

[jeffxtang]

What does this PR do?

Added examples (Section 4) of using Llama Stack 0.1 distro on together and Llama 3.2 to answer questions about an image with LS Chat and Agent APIs.

In short, provide a summary of what this PR does and why. Usually, the relevant context should be present in a linked issue.

• Addresses issue (#issue)

Test Plan

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• tests you ran to verify your changes with result summaries.
• provide instructions so it can be reproduced.

Sources

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Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• Ran pre-commit to handle lint / formatting issues.
• Read the contributor guideline,
  Pull Request section?
• Updated relevant documentation.
• Wrote necessary unit or integration tests.

[ashwinb]

Thanks @jeffxtang

[yanxi0830]

@jeffxtang This change is failing tests:

pytest -v -s --nbval-lax ./docs/getting_started.ipynb