This is about making the loaders compute a new hash for every new content we are actually loading.
This new hash is blake2s256 (length 32) - https://docs.python.org/3/library/hashlib.html#blake2.
Impacts:
- [ ] swh-model
- [ ] swh-storage
- [ ] db schema
Related T692 (about recomputing new hashes for the contents already stored in our storage).