Support for google embedding models such as text-embedding-004

[Haripritamreddy]

Google's embedding models like text-embedding-004 are mentioned as supported in the docs but we have no option to set them yet. We can do EMBEDDINGS_PROVIDER=google and EMBEDDINGS_MODEL=text-embedding-004 as its free. We can still use it by using litellm and spinning open ai api compatable server but this is more straightforward.

[rudolfjs]

Seconded, this would be a great addition.

[falkenbt]

Looks like there is a PR https://github.com/danny-avila/rag_api/pull/124 which would need some love. I also would like to see this, this is a blocker to roll it out futher in our google context.