Add the device authorization endpoint

[oliamb]

This is a follow-up PR proposal for issue #626. It implements Section 3.1 and Section 3.2 of RFC8628. PR #640 is related and arguably more advanced. But it is a bit old now and relates to the draft specification.

This is my first submission here. I think I followed the Contributing Guidelines, but please let me know if I am doing it wrong.

[dopry]

@oliamb do you have time to address the lint issues, that might help get this on a maintainers radar for review.

[oliamb]

Thanks @dopry. I did not even see that there was a lint issue. This should be fixed now.

[auvipy]

lets wait for the CI

[oliamb]

The linter fails at other points now, but I can see this is from code outside the original PR. I rebased my branch on top of the master yesterday. I don't think I should fix files outside the PR scope, WDYT? I don't manage to get consistent results on my local with the linter because I think the linter libraries' versions are not pinned (i.e. they are installed through the command pip install black codespell mypy pytest ruff safety).

[dopry]

I would treat upstream lint issues as out of scope, if I did want to fix them I would submit it as a separate PR.

[ondrados]

Hello, what is the current status? Can this be merged?

[dopry]

@auvipy do you have any thoughts on clearing the lint issues?