[CBBS] [Cloud] Not possible to import archives which exist at the root of the remote bucket

What's the issue?
The backup service requires that users provide a "repository path" when creating/importing repositories in S3. I believe this means that you can't import repositories which are created by 'cbbackupmgr' who occupy the whole bucket.

Although, I haven't tested this; S3 might be like Linux, in that you can have multiple path separators, which are ignored i.e. you could just use '/' as the repository path, however, we shouldn't be relying on this behavior.