Switch to azure openai

[cwaddingham]

Problem

Revised the template to use Azure OpenAI instead of OpenAI.

Solution

This was a rip-and-replace, focused on the embeddings service and the chat interface. It completely replaces the use of OpenAI as the default LLM with Azure OpenAI, and incorporates some Azure-specific chat streaming methods.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• [ x] New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• Infrastructure change (CI configs, etc)
• Non-code change (docs, etc)
• None of the above: (explain here)

Test Plan

Deployed locally and confirmed to work as expected.