fix diff calculation bug around deleted edges

[ajtmccarty]

IFC-753

Various fixes following the last round of diff updates

• use branched_from instead of created_at for diff calculation b/c branched_from is updated following a merge or rebase
• clean up how we do diff recalculation following changes to how we store the diffs in 0.16.2
• remove unchanged values from the calculated diff
• fix an error I found by chance in relationship deletes where we would create OWNER and SOURCE edges in the database instead of HAS_OWNER and HAS_SOURCE
• fix the diff rebase tests to look for the correct data (no conflicts after a rebase)
• updates to the DiffAllPathsQuery
  • to ignore nodes/attributes/relationships added and deleted within the diff timeframe
  • remove a few filters that prevented correctly handling deleted relationships within a deleted node
  • move the logic to gather previous values and peer IDs to the end of the query, hopefully split this out into its own separate query