Add support for OIDC based SSO

[ktbartholomew]

This addresses #6616.

• Adds configuration fields for OIDC provider URL, client ID, and client secret
• Adds core API endpoints to facilitate an access token OAuth flow with an OIDC-compliant provider (like Dex, see Dex for authentication #5358)
• Creates user (in database) from OIDC claims if not present, or authenticates as that user if present.

Feedback welcome, as I'm sure there will be lots of opinions from more experienced contributors about things that I haven't done correctly 😄

[steven-zou]

@ktbartholomew

Thanks a lot for submitting PR to cover the fantastic OIDC supporting which the whole community is looking forward to. However, based on the Harbor governance model, the changes should be summarized as a proposal and submitted to the community for a widely discussed before raising code PRs. Only the proposal is accepted after review and voting by maintainers, the related code changes (PRs) can be accepted.

Is it ok to draft a proposalto describe your main ideas and let the community have a review? @ktbartholomew

Moreover, a suggestion, many other community users have interested in this feature, maybe you can have a try to contact them to set up an OIDC workgroup to discuss and deliver the feature together? @ktbartholomew

[reasonerjt]

@ktbartholomew
Thanks for the valuable work!
Actually we do plan to provide oidc support in 1.8.0 timeframe (Before end of April).
The proposal was delayed and planned to be submitted by the end of Feb, if you are interested we can work together to define the scenarios in the proposal and implement the feature.

[ktbartholomew]

@steven-zou It looks like a proposal had been made, but a revised draft is being worked on privately (see goharbor/community#17 (comment)). I'm happy to review and contribute to the proposal, but want to make sure I'm helping in the right place.

[reasonerjt]

@ktbartholomew
Do you have a preferred way to more interactive communication in addition to this PR? Email? Slack(cloud-native.slack.com)?

[ktbartholomew]

@ktbartholomew
Do you have a preferred way to more interactive communication in addition to this PR? Email? Slack(cloud-native.slack.com)?

Slack is good, didn't know you had a workspace. Joining now!