Support models compatible with OpenAI format

[StreetLamb]

Expose openai's base_url in mcp_agent.config.yaml file so that providers using OpenAI format such as Ollama, LiteLLM, Gemini (in preview) and Deepseek etc. can be used without having to write custom classes for each of them. Included an example to demonstrate its usage.

Closes #19

[saqadri]

Amazing!!!

[tihomir-kit]

Sorry to parachute in, but would this be the correct way to use this with the Gemini 2.5 Pro Preview?

mcp_agent.config.yaml

openai:
  base_url: "https://generativelanguage.googleapis.com/v1beta/openai/"
  default_model: "gemini-2.5-pro-exp-03-25"
  api_key: "<my_api_key>"

What did you use for base_url ?

Then I imagine you would simply use this:

llm = await finder_agent.attach_llm(OpenAIAugmentedLLM)

And it should just work? Or am I misunderstanding something?