Spring-ai Add support for Solar Model Chats

This PR is related to #1712.

Added features: - SolarApi: Implementation of the api documentation - SolarChatModel: Implementation for Solar backed by SolarApi

This API is compatible with the OpenAI API. The embedding functionality will also be added in the near future. I believe adding this model will greatly benefit Korean users.

If needed, I would be happy to provide the API key.

Thank you.