Issue Summary

JCMA already has an attachment only and configuration only backend mechanism. It would be good to have a "data only" migration so the tool can be leveraged to migrate issues/attachments without the whole complexity of fixing configuration metadata that is not supported in Cloud (e.g. workflows)

For example, having the ability to migrate issues/attachments and associating them with the default vanilla schemes/workflows/etc so that admins have the ability to migrate the data easier and do post-migration config mapping later.