Switched to the new minder-specific API

This PR switches the entire pipeline over to the Minder-specific API. Review but please do not merge until all four projects are ready to me merged.
These models provide no value. They are just skeletons that the developer needs to fill out.

Unless of course they are here to provide default values for fields, in which case those defaults should be decided server-side for missing optional properties, and for missing mandatory properties the server should respond with `400` or `422` because that is a client-side programmer error. Using one of these constructors would otherwise mask that error.