feat(oauth2): simple userinfo endpoint

[hardviper]

Summary

This solves the oAuth2 authorization issue in openproject when openproject is the client.
Added endpoint that returns a minimum set of user information.
This is very necessary in my openproject integration with nextcloud.
I hope this helps someone else.
Thanks to @jlallana for suggesting this solution in PR #19934.

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
  • \OCA\OAuth2\Tests\Controller\OauthApiControllerTest
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[hardviper]

@skjnldsv Is there anything else I can add to help you accept this?

[skjnldsv]

@skjnldsv Is there anything else I can add to help you accept this?

I pinged the proper devs, let's see :)
Does this supersede #19934 ?

[hardviper]

@skjnldsv This adds the user_info endpoint, but does not add the discovery.
Now I have fixed the problem noted by the bot, and also added some more userinfo fields.

[skjnldsv]

There was an issue with the rebase, please fix it

[hardviper]

@skjnldsv Ready! I have corrected! I don't understand how these commits got here.

[ChristophWurst]

I'm fine with the endpoint. Some instructions for testing would be appreciated.

The name split logic probably doesn't work for all names. If we can I would strongly favor removing it and only exposing the full name.

[kesselb]

Is there an addition of last name and first name fields in the roadmap?

Forwarded your question.
Please ping me if we haven't replied within the next 4 weeks.

[hardviper]

@kesselb Do you have an answer for the roadmap?

[kesselb]

Do you have an answer for the roadmap?

Having fields for first name, last name, title or prefix as addition/replacement for the full name field is something we want.

However, it's not scheduled for the current or next iteration.

https://github.com/H2CK/oidc could be interesting for you as well.