Provide a way to convert from KabaneroSpecStacksPipelines to StackSpecPipelines

[kaczyns]

See this review comment:
kabanero-io/kabanero-command-line-services#109 (comment)

Copying a pipelines configuration from the Kabanero CR to a Stack CR is going to be a common thing to do. We should provide a convenience method for doing this. The JSON representations are idential but the backing Java objects are not. It should just be a matter of round-tripping to JSON and back again.