Switched to the PagingAndSortingRepository for Mongo.
Added an the Pageable interface to the Part Dto.  This should be
helpful for pagination from the backend.

Added a JSON implementation to bring back all parts from the mongo
parts collection.
Added better implementations to the Pageable interface methods for
a Part Dto.
Added copy-pasted code from Dojo reference guide.  This is using the
JSON Rest store.  I'm not sure what to do with it yet.  It does not
have a valid implementation on the page at this time.