Add an AI model, Deepseek

[tclxtianxiang-yu]

Deepseek is popular now, and I hope to use deepseek in ai commit in gitlens.
https://www.deepseek.com/

[eamodio]

I've added support for V3 & R1.

Can you please try this out in tomorrow's (v2024.M.DDxx) pre-release edition of GitLens? Thank you so much!

You can switch to the pre-release edition of GitLens, by clicking on the "Switch to Pre-Release version of this extension" from the Extensions view.

[sergeibbb]

I'm taking this for verification

[sergeibbb]

@eamodio

It asks for a HuggingFace API Key every time user switches the model, even if I switch between different models of Copilot. But it might not be connected with DeepSeek. I'll check.

UPD. Right. I've checked in 4d52732 and it works as usual. So, the problem is not connected to this update. I'm approving.

UPD2. It's related to #4020
https://github.com/user-attachments/assets/0830ac4d-4876-4d78-bbf6-d5141b050d0c

[sergeibbb]

@eamodio

Well, I've approved as "verified", but now I'm not sure if I should to. I see that it tries to send requests by seeing the error, so it's supposed to work. But I cannot see the result because it's paid.