Added printing of DB name to migrate, to give "Result: X" messages context. It seems like this is a built in function of the Gradle task object, so it would be better if I could find a way to customize that line, but I haven't figured that out yet.
Revised, tested version. I'm not really happy with FlywayContainer, but building it mostly in FlywayPlugin was the only way I could find to make the properties extension-aware. This allows for the sub-properties to be initialized as extensions within the main extension.