Remember the previous write enabled primary node

Remembers the previous write enabled primary node. This will be used to determine unreplicated writes from the previous write-enabled primary after a failover.

A new column is needed as replication jobs do not always originate from the primary node. Reconciling from a secondary to a read-only primary in an attempt to get the complete data set to the primary after a failover would produce replication jobs from the secondary to the read-only primary. This makes it difficult to track the previous write-enable primary solely from the replication jobs.

Related to #2683 (closed) and #2717 (closed)