Google drive doesn't allow the btime (created time) metadata to be
updated when updating an existing object.
This changes skips btime metadata if we are updating an existing
object but allows it otherwise.
- fetch metadata with listings and fetch permissions in parallel
- only write permissions out if they are not inherited.
- make setting labels, owner and permissions work controlled by flags
- `--drive-metadata-labels`, `--drive-metadata-owner`, `--drive-metadata-permissions`