[Feature Request] Support OAuth2 Device code authorisation flow

I would like httpyac to support the OAuth 2.0 Device authorization grant for the openid variable replacer.

Ref. RFC8628 Example of usage: Microsoft Identity platform

Proposal for httpyac:

GET https://graph.microsoft.com/v1.0/me
Authorization: openid device_code msidp

Reason:

This is a great way of authenticating using applications where you cannot/don’t want to modify the redirect Url, and don’t have access to/don’t want to leak the client secret. And contrary to the implicit and hybrid authorization flows, the device code flow hasn’t been deprecated by the OAuth standard and best practices.

[fredrikhr]

@AnWeber I think this looks great! I tested it with Microsoft Identity platform and it works like a charm! As expected it keeps the session and even picks up the refresh_token if you specify the offline_access scope.

I also managed to recompile the VS Code extension with the new code and tested the UI features of the flow. Everything checks out fine! 👍

[fredrikhr]

Can you add another button to copy the user_code to the clipboard?