fix #231 - Add version parameter to openai-chat provider config to support different API versions

[CsBigDataHub]

• Add version parameter to openai-chat provider config to support different API versions
• Version 1: Uses max_tokens parameter (for Mistral AI and older OpenAI-compatible endpoints)
• Version 2 (default): Uses max_completion_tokens parameter (for OpenAI and modern endpoints)
• Fixes Mistral AI 422 errors by allowing configuration of appropriate token parameter
• Supports both provider-level and model-level version configuration with provider taking precedence
• Maintains full backward compatibility by defaulting to version 2
• Automatically removes conflicting token parameters based on version
• Prevents sending version parameter to external APIs
• Includes comprehensive integration tests
• Updates documentation with examples and schema
• Adds CHANGELOG entry under Unreleased section

[CsBigDataHub]

@ericdallo please do NOT merge, I am having tool call issues

LLM response status: 400 body: {"object":"error","message":"Tool call id was 7878-452755744 but must be a-z, A-Z, 0-9, with a length of 9.","type":"invalid_function_call","param":null,"code":"3280"}

[ericdallo]

@CsBigDataHub let me think a little bit, I don't want to have different functions, apis or complex things just to one or other param more or removed, I want user to be able to customize that like we did for responses adn anthropid, we may manage to do the same, let me take a look