fix(aw-client-rust): make create_bucket_simple useful

[hapm]

create_bucket_simple should expose the created bucket for later use. This would allow to expose the id, which can be generated based on the bucket name given and the hostname, what in turn leads to simpler creation of a new Bucket, as intended by the function.

[ErikBjare]

This is a breaking change. I suggest to keep the original behavior to avoid mishaps.

Suggested change

	id: format!("{}_{}", bucketname, self.hostname),
	id: bucketname.to_string(),

If you want your ID with a hostname suffix, better pass a different bucketname instead of adding this assumption to the create_bucket_simple method.