obo: list buckets

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>
obo: fix usage

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>
obo: create bucket

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>
obo: bucket versioning enable / disable

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>
obo: bucket stat

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>