Improve the ObjStorage inheritance tree and its documentation
- The docstring of the ObjStorage implementations have been updated to reference the one present in the base class.
- Make the base API ObjStorage an Abstract Base Class for python. This add more security when a new ObjStorage implementation is created.
- Also, the filtering object storage now use this feature to make its extension easier.
- Remove duplicate test for the PathSlicingObjectStorage.
- Factorize hash computation into objstorage
- Rename an argument that didn't follow the API
Migrated from D95 (view on Phabricator)