Add support for projected service account tokens in `auth-provider-gcp`

[theobarberbany]

From kubernetes 1.33 (in alpha) kubelet will support passing service accounts to kubelet credential providers.

This will allow workloads to pull images based on their own runtime identity without long lived / persisted secrets, and avoid needing a kubelet/node based identity to pull images.

The relevant enhancement is kubernetes/enhancements#4412.
KEP: https://github.com/kubernetes/enhancements/blob/master/keps/sig-auth/4412-projected-service-account-tokens-for-kubelet-image-credential-providers/README.md

This issue is intended to track implementation progress for auth-provider-gcp.

This addresses #760

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[theobarberbany]

/remove-lifecycle stale

[k8s-triage-robot]

The Kubernetes project currently lacks enough contributors to adequately respond to all issues.

This bot triages un-triaged issues according to the following rules:

• After 90d of inactivity, lifecycle/stale is applied
• After 30d of inactivity since lifecycle/stale was applied, lifecycle/rotten is applied
• After 30d of inactivity since lifecycle/rotten was applied, the issue is closed

You can:

• Mark this issue as fresh with /remove-lifecycle stale
• Close this issue with /close
• Offer to help out with Issue Triage

Please send feedback to sig-contributor-experience at kubernetes/community.

/lifecycle stale