[FEATURE] Supporting OpenAI API and other service endpoints

[nociza]

Is your feature request related to a problem? Please describe.
N/A

Describe the solution you'd like
Currently the solution only allows the usage of Azure OpenAI, which is very limiting. Our specific use case would require using custom finetuned models which can be accessed as a OpenAI compatible web server. It would be great to add a field the config to allow for other model endpoints other than Azure OpenAI.

Describe alternatives you've considered
I've considered using graphrag directly and writing out a solution myself.

Additional context
N/A