Create relationship table between pub and pub_history

[LegalizeAdulthood]

pub references pub_history and pub_history references pub.

This creates an awkward situation when you add a publication, you first add to the pub table and get the id for that and add to the pub_history table, then you have to update the pub table again to reference the new pub_history row.

Fix this by creating a table that explicitly links publications to their edit history.

The pub table would have it's pub_history reference removed. The new table would be used instead to obtain the current pub_history entry for a pub.

Adding a publication would be:

• add a pub row
• add a pub_history row using pub_id
• add a pub_revision row using pub_id, pub_history_id

[LegalizeAdulthood]

See Paul's design notes about the pub/pubhistory table origin.