Use Portkey-AI Gateway as a proxy to send requests to LLM providers

[wilderlopes]

New feature

We would like to have a supervisor that can route requests to the appropriate LLM. miniogre can work with multiple LLMs, but currently we implement a unique API for each one of them.

The Portkey-AI Gateway repository provides a clean, easy way to proxy all the requests to LLM APIs.

Basic approach

Functions like this one in the miniogre code base, should be deprecated in favor of the gateway mentioned above. This will result in a cleaner code, easier to manage, because we won't need to write a new function every time we add a new LLM provider.