Guide readme fix

[raghotham]

What does this PR do?

Fixes readme to remove redundant information and added llama-stack-client cli instructions.

Before submitting

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