Add Readme in Api Server example

[taranjeet]

🚀 The feature

• add readme for api-server.
  • add setup instructions
  • explain each endpoint
  • Curl call for each endpoint so that anyone can quickly try it out
  • How to set OpenAI key in environment variables

Motivation, pitch

Improve the example so that anyone can easily try it out.

Alternatives

No response

Additional context

No response

[AshishKingdom]

hello @taranjeet I want to work on this one. Please assign me this issue.