[feat] Add convenience functions for extracting zipped submissions

[vpchung]

Describe The Problem To Be Solved

Previously, only the BraTS challenges had file submissions where participants submitted zipfiles and tarfiles. But as we move towards supporting more complex challenges that evaluate more than just a single flat file, it would be make sense to move these functions over to a more commonplace package, such as here.

That way, infrastructure support is not recreating this script each time it's needed.

(optional) Suggest a Solution

Move this script over to cnb-tools.