swh.deposit.models: Upload deposit archives to dedicated folder
This allows to avoid the clash names when depositing multiple archives with the same name.
This serves the same purpose as file disambiguation needed to solve the issue. In a, most possibly, simpler manner than changing altogether the current file storage implementation.
The folder name is a timestamp to the microsecond. So it might not be completely bulletproof though.
Related to #2393 (closed) Related to !74 (closed)
Test Plan
tox
Migrated from D3197 (view on Phabricator)