Finish initial functional implementation of radosgw-rest-admin

* Rename executable to avoid mis-imports (due to cyclic importing)
* Fix creation of Buckets (depends on boto)
* Add user-bucket-create command which creates and links a user and a bucket
Properly rename the the methods to reflect on their actions
Merge pull request #1 from TelekomCloud/refactor-and-add-functionality

Refactor and add functionality