Support UPDATE/DELETE

[HolgerKache]

Cloudant sink connector supports append-only today. There are two different schemes for the _id using the replication setting as documented here: https://github.com/cloudant-labs/kafka-connect-cloudant#cloudant-as-sink

With replication=true the sink connector would honor the document _id during insert into the target db but does NOT perform UPDATE or DELETE on the document. So in a way the term “replication” is misleading.

To actually support replication we need to add information to the event that carries the action details (INSERT, UPDATE, DELETE) along with the source document _id and the document body.