[serverctl] complete the schema-diff command with options that will fix & enhance it.
Notably:
- filter out eids (doesn't make sense for the filesystem schema)
- handle permissions, trying to detect the default ones
Needs yams #174042.
Closes #2996547.
usr/lib/PY_VERSION/*-packages/cubicweb/server/
usr/lib/PY_VERSION/*-packages/cubicweb/hooks/
usr/lib/PY_VERSION/*-packages/cubicweb/sobjects/
usr/lib/PY_VERSION/*-packages/cubicweb/schemas/
usr/share/cubicweb/migration/