Break up google-cloud repo

Any time one dependency in the google-cloud repo needs to be updated, they all need to get updated due to the massive web of dependencies they all have. This makes it very painful to update any library to get bug fixes or improvements.

There is no need for them to all be in the same repo and plugin jar. They should be grouped by technology. For example, all bigquery plugins in one repo, all GCS plugins in another, etc.