Support OpenAI and compatible embeddings

+1. This isn't something I'm likely to work on in the near future but if you or someone else wants to that would be great. I think making some kind of plugin type for doing the embeddings, and leveraging that, would probably be the best way to handle this. Also in my little bit of looking into this earlier I noted that you'll need to use one of the 2 newer Open AI embedding models because those ones support a configurable vector size. The older models do not, and they default to a vector that is too large to store in a Dense Vector field.