Replace ascendant/descendant values with uniform values

[Bushstar]

On token split we add a record of that split to Governance variables, the previous record was missing the multiplier amount which is not available elsewhere after the split has completed. This updates the record to include complete information and have the same record for the old and new token.

New

• listgovs / getgov entry for token split as follows.
  • key - v0/token/ID/migration
  • value - OLD_ID/MULTIPLIER/NEW_ID/HEIGHT

Breaking

• Requires reindex.
• Removes descendant / ascendant keys from listgovs / getgov