Configurable Base URL for azure-ai-openai

[GTarkin]

Hello,

would it be possible that the base url for chat completion request could be passed from the outside? On my project we have the requirement to dock multiple ai vendors for chat completions to the application. It seems that the OpenAI-Api format established itself as quasi-standard that is also used by other cloud providers.

The azure-ai-openai package assumes, that as soon as you set an URL other than the null or the OpenAI-API url as endpoint in https://github.com/Azure/azure-sdk-for-java/blob/main/sdk/openai/azure-ai-openai/src/main/java/com/azure/ai/openai/OpenAIClientBuilder.java, the endpoint will be a azure endpoint, i.e. the builder will create a instance of OpenAIClientImpl instead of a NonAzureOpenAIClientImpl. Relaxing that requirement would make the client more flexible and it could also access other vendors.

The idea is to enhance the builder in a way that you could specify that you want to call a endpoint that is not a AzureEndpoint and the builder will return an NonAzureOpenAIClientImpl.

Would a pull-request proposing such a change be accepted?