Refactor litellm_ai_handler.py and update requirements.txt

- Replace retry library with tenacity for better exception handling
- Add verbosity level checks for logging prompts and AI responses
- Add support for HuggingFace API base and repetition penalty in chat completion
- Update requirements.txt with tenacity library

requirements.txt

@@ -25,4 +25,5 @@ starlette-context==0.3.6
 tiktoken==0.5.2
 ujson==5.8.0
 uvicorn==0.22.0
+tenacity==8.2.3
 # langchain==0.0.349 # uncomment this to support language LangChainOpenAIHandler