Code to define modeltype RM-2380

create a modeltype table used by models and pfts. The table is
initialized with the types already in the models (not pfts). All models
and pfts are associated with a modeltype next.
User can add/edit modeltypes and see the pfts/models associated with it.
"save" is a little confusing here since it does nothing with a format you've just added or one you added earlier but didn't change.  Perhaps "save changes" or "update" would be at least a little clearer.  Best would be if it were grayed-out (or maybe not even there) when you haven't changed anything, but I'm not going to make you do that.