Support GCP workload identity for authentication

[nia-potato]

Instead of using the current way using exported service account credentials, we should change to the more secure way of authenticating an application by using workload identity

currently infrawallet is the only application we internally use to access GCP endpoints that require a exported service account key

il try contribute to it, just opening a issue for now to track.

[gluckzhang]

Hi @nia-potato , thanks for this proposal. I believe it will be very helpful for InfraWallet GCP users. Look forward to it!