System checks for duplicate records on import

NOTE: This feature is NOT planned for release in v1.5.

User Story

System checks for duplicate records on import
    * import either continues with batch if failFast=false
    * or import fails immediately if failFast=true

Related User Stories:

Import User Story Summary

Derived Stories:

User Story: System checks for duplicate records on import
Service Story: Consumer gets report of duplicate records on import