Support private_key_jwt in OIDC Provider

[NickMeves]

The private_key_jwt authentication method (as opposed to the client secret) in the OIDC spec seems to be the only aspect we are missing from our OIDC implementation that the LoginGov provider requires that we can't meet with the OIDC Provider

Expected Behavior

Let's support that private_key_jwt in the generic OIDC Provider so LoginGov (and any other IdPs that support it) can use it.
And then let's look to deprecate LoginGov.

Current Behavior

Only client secret token redeem authentication is supported.

Possible Solution

https://kb.authlete.com/en/s/oauth-and-openid-connect/a/client-auth-private-key-jwt

Look at existing LoginGov provider for implementation details.

Context

Let's simplify the codebase, specifically in the Providers which have a lot of duplication.

[NickMeves]

CC: @timothy-spencer

With this plus nonce support in this PR: #967 -- Is their anything else missing from the generic OIDC Provider that Login.gov needs?

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[github-actions]

This issue has been inactive for 60 days. If the issue is still relevant please comment to re-activate the issue. If no action is taken within 7 days, the issue will be marked closed.

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[ghermana]

Could not find a way to use private_key_jwt with OIDC. Am I missing something? The issue still seems open

[tuunit]

Hi @ghermana,

yes indeed, as of yet this isn't implemented and support. A PR was recently opened: #2305

[ghermana]

Thank you for the link @tuunit , please let me know if there is anything that can be done to help with the PR

[tuunit]

@ghermana if you want to, give it a code review and / or build the branch locally and test if it works for your use case as well.

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This issue has been inactive for 60 days. If the issue is still relevant please comment to re-activate the issue. If no action is taken within 7 days, the issue will be marked closed.