[Feature]: General OIDC support

[cailyoung]

Related Problem

#10583 requests GitLab, but I think there's more value in adding a 'general' OIDC configuration option.

The Elevator Pitch

The GitHub Trusted Publisher feature uses OIDC under the hood, it's just that the UI is constructed to help users construct valid subject claims. Many other tools support OIDC token handling but we currently cannot use them to safely publish our packages; instead we have to stay with the (relatively riskier) static API token approach.

Additional Context and Details

At work we built two wizards, one for GHA because it was so prevalent, and another with generic inputs: https://octopus.com/docs/octopus-rest-api/openid-connect#create-an-oidc-identity-for-a-service-account

[pranathibora14]

Thanks for the suggestion and input, @cailyoung!

We agree that broader OIDC support for trusted publishing is valuable. That said, this is bigger than NuGet alone. Supporting additional OIDC providers requires alignment with the identity and security platform layers that trusted publishing is built on, so it's not something we can tackle in isolation. We'll keep this on our radar as we evaluate expanding trusted publishing to additional providers.