Consider splitting Google Provider

The `Google` provider is huge. It's by far the biggest provider out there and it has a number of sometimes more closely coupled and sometimes not coupled at all (leveldb) operators. We should consider splitting the Google operator into smaller pieces, but that would involve some more decisions: * what to do with common part * what should be the split ? Per service? Per cloud ? * how to manage dependencies between different provider * how to manage transition and backwards compatibility This is more of opening the discussion than making decisions yet.