Spring-ai Add support for Solar AI models

Hello,

I have added a Solar model client. Solar is an LLM and embedding model from Upstage, a company based in South Korea, and is especially optimized for Korean and Japanese embeddings.

Links - Upstage - Solar Embedding Benchmarks

If needed, I can provide my API key for your use.

Comment From: markpollack

Hi. Is this model have openai API compatability? That would be a preferred direction to ease with maintenance.

Comment From: jsilverman26

@jee14 @markpollack Hi, Solar model has OpenAI API compatibility. check this. Upstage API Documentation

from openai import OpenAI # openai==1.52.2

client = OpenAI(
    api_key="UPSTAGE_API_KEY",
    base_url="https://api.upstage.ai/v1/solar"
)

Comment From: jee14

Hi. Is this model have openai API compatability? That would be a preferred direction to ease with maintenance.

Yes. Please refer to @jsilverman26 comment. There are a lot of features that need to be added to this PR (e.g. streaming), but I think more people can participate in the contribution to this model if it merges.