Added Conversation API to JS SDK

[ConstantinChirila]

Description

This PR adds comprehensive support for the Dapr Conversation API to the JavaScript SDK, enabling developers to interact with Large Language Models (LLMs) through Dapr's conversation components. The implementation includes both HTTP and gRPC protocols, complete type definitions, and a working example.

Issue reference

#706

Checklist

Please make sure you've completed the relevant tasks for this PR, out of the following list:

• Code compiles correctly
• Created/updated tests
• Extended the documentation

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
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Additional details and impacted files

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[WhitWaldo]

This looks great - thank you for putting all of this together. I just updated the protos to 1.16 on the repo in master. Could you update your PR to ensure all the test pass so we can merge this in for the release?

Thank you!

[WhitWaldo]

Is this right? Did it bump to v1.0-alpha2?

[ConstantinChirila]

@WhitWaldo Yes, I've added this to the quickstarts as well. This is the new API for the conversation. There is no longer streaming, it just has tooling right now.

Ill have a look at the tests and fix them as soon as I can. Thank you for the review!

[WhitWaldo]

One more thought - I don't think we need both an HTTP and a gRPC implementation as the SDK need only do one of them (typically preferring gRPC as it's typically the more complicated one).