Investigate replication of column additions in structs

[patduin]

As a user of CircusTrain I'd like to know if I can change struct columns without breaking replication

Acceptance Criteria:

• Write an integration test for the following scenario.
  • Table (with a column of type struct) is replicated
  • column is update on source to contain extra columns. (struct type change)
  • Type change is replicated to target table correctly.