[Draft] Add support for OpenRouter endpoints

[matthieuEv]

Following this comment: #116 (comment)

[matthieuEv]

@jjmata i dont think that i'd be able to do this task before next week, but you can assign it to me, and put it in a milestone 👍

[jjmata]

Actually, you should probably take over #17 ... right, @matthieuEv?

[matthieuEv]

actually yeah 👍