Base BaggedTrainingResult on models, not results
Base BaggedTrainingResult on models, not results

The bagged models map many underlying instances, so they can
get heavy.  We can reduce that a bit by discarding the TrainingResult
metadata after extracting feature importance from it.  The rest of
the metadata comes from the bagger itself.

CitrineInformatics/lolo,CitrineInformatics/lolo