graph dataset: uniform file names
The naming of edge files in the graph dataset is inconsistent. We should use as from/to node types the short prefixes of SWH PIDs, in particular:
- s/file/cnt/
- s/snapshot/snp/
- s/release/rel/
- s/origin/ori/ (not strictly speaking a type of node, but a 3-letter prefix would be consistent with the rest)
The README file should be updated to match.
Migrated from T1742 (view on Phabricator)