[Feature] Support for Google's Gemini!

[danimesq]

Add a GPT <-> Gemini switch, ranging from Pro to Ultra (as there's GPT 3.5 and 4).

Can use the already available API for Gemini: https://ai.google.dev/

[danimesq]

Done, thanks!

[HamedMP]

I see it's closed but I still can't use it. When I dont' set the API key, it says you can't use this model (gemini-1.5-pro-001) and when I set it, I get "invalid API key" but I can successful curl it from console.

[danimesq]

Gemini only available in Long Context mode. True, this issue should be re-opened, that was a confusion.

[Stevengre]

I would like to request that Pro users be given the opportunity to try Gemini. Currently, it seems that an API needs to be added to access Gemini.