Feature Request: Add Azure OpenAI

[rmporsch]

Many enterprises are not using OpenAI but Azure OpenAI. It would be great to have the ability to change the endpoint for the openai library, through an ENV or other means.

Otherwise we will need to re-create several of the designed tests and metrics with custom implementations.

Understand that adding additional LLMs, such as Gemini, might be out of scope for a while.