N5 library implementation using Google Cloud Storage backend.

This test uses OAuth 2.0 authentication to run unit tests using actual Google Cloud Storage backend. It is excluded from the test run configuration by default and requires a few steps to set up:

1. Create a project in the Google Cloud console.
2. Go to APIs & services and choose Create credentials → OAuth client ID.
3. Once created, put the provided client_id and client_secret fields into src/test/resources/client_secrets.json.
4. Enable Storage API and Resource Manager API.

This approach allows to obtain temporary security credentials and a refresh token that can be used to obtain new short-term credentials. The test shows how to create a Storage API client in a way that it handles refreshing access tokens internally. The refresh token remains valid as long as the user has not revoked application access.