Allow included application to create versions

[awead]

If FedoraMigrate is included in another application that is already creating versions for attached files, then FedoraMigrate should not create versions when migrating. Otherwise, there are two versions for every one original version. Here we pass an option that lets the included application create the version. By default, however, FedoraMigrate will create the versions such as if it is used outside the context of a Hydra application, or one in which no versions are automatically created.

[jcoyne]

While this will work for the SS use case. I'd bet there are some applications where application_creates_versions needs to be settable at a finer level of granularity.

[awead]

@jcoyne by default, FedoraMigrate will look to the defined datastream's hasVersions?. Otherwise, we're passing the logic off to the application that's including the FedoraMigrate gem. So if there was more granularity, you'd provide that in the included application, or if you were just using the gem alone, you'd model your objects with datastreams that were or were not versionable as needed.