Automatic merge from submit-queue (batch tested with PRs 50579, 50875, 51797, 51807, 51803)
oidc auth: make the OIDC claims prefix configurable
Add the following flags to control the prefixing of usernames and
groups authenticated using OpenID Connect tokens.
--oidc-username-prefix
--oidc-groups-prefix
```release-note
The OpenID Connect authenticator can now use a custom prefix, or omit the default prefix, for username and groups claims through the --oidc-username-prefix and --oidc-groups-prefix flags. For example, the authenticator can map a user with the username "jane" to "google:jane" by supplying the "google:" username prefix.
```
Closes https://github.com/kubernetes/kubernetes/issues/50408
Ref https://github.com/kubernetes/kubernetes/issues/31380
cc @grillz @kubernetes/sig-auth-pr-reviews @thomastaylor312 @gtaylor
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