UI: replace chatbot with azure openai

[shreyashankar]

Currently the frontend AI tools are using regular openai. We should switch to azure openai; with an option for users to use regular openai if they provide their own key.

This requires the following changes:

• Allow /api/chat route to accept azure requests too (by default, actually)
• Add a switch to the AI Chat panel component for azure or regular openai
• Create new azure deployment dedicated for docetl (todo)
• Set up azure keys in the frontend & some mechanism to cap the usage
• Set up logging
• Set up cron job that reads the total cost from the table and notifies us on slack if the usage has exceeded a threshold