✨ Support Embedding API

[roma-glushko]

Add a new set of API to support embeddings:

• come up with the unified embedding request/response schemas
• add a new model type to the routers config
• define at least one provider with embedding capabilities

[avinashkurup]

Hello @roma-glushko,

Following up on our recent Discord thread, we are currently evaluating your project for a use case that involves Retrieval-Augmented Generation (RAG) and embedding as key components.

We are very excited about the LLMOps features in this project and would love to leverage them for our needs. Could you please let us know if the embedding API is planned for introduction in the near future?

Thank you for your assistance!