Adds logging by default, other mods to allow use with litellm

[emeryberger]

Incorporates mods to enable use with litellm and other providers.

Logging is now on by default. Clients downstream will likely want to use this to adjust the logging level so it only reports errors (or warnings).

# Turn off most logging                                                                                     
from llm_utils import logging
logging.getLogger().setLevel(logging.ERROR)