feat: logout with ueberauth_oidcc

[paulswartz]

Summary of changes

Support logging out based on the Ueberauth.Strategy.Oidcc strategy, and API access via the Keycloak API. Based on top of #952 .

Reviewer Checklist

• Meets ticket's acceptance criteria
• Any new or changed functions have typespecs
• Tests were added for any new functionality (don't just rely on Codecov)
• This branch was deployed to the staging environment and is currently running with no unexpected increase in warnings, and no errors or crashes.

[nlwstein]

Overall, this looks good to me, just a couple non-blocking q's 😄

[nlwstein]

Does this provide a session that never expires?

[paulswartz]

The opposite; it expires immediately so that if it does happen to make it outside of the API (which it shouldn't) it won't be usable.

[paulswartz]

It should be a session that expires immediately, but I will double-check that's how Guardian treats it (or if there's another way to implement this).

The issue I ran into (and I think this is true of the existing implementation) is that the API returned a session cookie that you can use instead of the API key, and I didn't think that was the normal approach for an API. We disable that now, but also set a 0-second TTL to ensure that if the token did leak out, it wouldn't be usable.

[github-actions]

Coverage of commit 372c279

Summary coverage rate:
  lines......: 88.8% (672 of 757 lines)
  functions..: 59.2% (515 of 870 functions)
  branches...: no data found

Files changed coverage rate:
                                                                     |Lines       |Functions  |Branches    
  Filename                                                           |Rate     Num|Rate    Num|Rate     Num
  =========================================================================================================
  lib/arrow_web/controllers/auth_controller.ex                       |73.1%     26|85.7%     7|    -      0
  lib/arrow_web/router.ex                                            |95.0%     20|43.8%    73|    -      0
  lib/arrow_web/try_api_token_auth.ex                                |92.9%     14| 100%     3|    -      0
  lib/arrow_web/try_api_token_auth/keycloak.ex                       |90.6%     32| 100%     5|    -      0
  test/support/fake_oidcc.ex                                         | 100%      1| 100%     1|    -      0

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