Support direct OAuth credentials with Google Cloud Storage

[mpiannucci]

Currently, Google Cloud Storage authentication is limited to service account keys. Many times, the service account is not accessible or a larger system is impersonating accounts to obtain credentials which come in the form of OAuth credentials. This is possible with object_store though:

apache/arrow-rs#5223

With this we need to expose a credential provider to python and rust users that allows for passing in OAuth token directly. This should also support refreshing as the tokens come with expiration dates