Add kotlin docs

[Riandy]

What does this PR do?

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

Docs update for Kotlin SDK release

Test Plan

Please describe:

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

Sources

Please link relevant resources if necessary.

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.

[Riandy]

Note: Feel free to review the PR and suggest changes, but don't merge it yet. We will merge this at the same time when we release the Kotlin SDK

[cmodi-meta]

@Riandy - Note the readme will need to be updated as well to replace the "TODOs"

[yanxi0830]

https://github.com/meta-llama/llama-stack/blob/main/CONTRIBUTING.md#building-the-documentation -- you could follow this instructions here to preview the documentation, and attach a screenshot in the test plan.

[Riandy]

[
Llama Stack Client Kotlin API Library — llama-stack documentation v3.pdf
](url)

How it looks on the docs following https://github.com/meta-llama/llama-stack/blob/main/CONTRIBUTING.md#building-the-documentation
cc: @yanxi0830

[ashwinb]

yeehaw!