Add step in pipeline to sync annotation assertions on inverses

[cmungall]

Originally discussed here:

• Ensure metadata fields are populated for inverse properties #51

See:

#815 (review)

1. We should avoid duplicating direction-agnostic metadata across inverse pairs
2. direction-agnostic metadata should go in the primary direction
3. the definition for the inverse direction should say "inverse of..."
4. comments, seeAlso etc that are direction-neutral should stay on the primary

This is good for ontology maintenance, but less good for the user. We should have a way of propagating 4 at release time. However we want to do this only for truly direction-neutral. E.g propagating most synonyms, xrefs would be wrong. We could do this with a "applies to inverses" axiom annotation