Replace data_file_paths with original_files

[avrohomgottlieb]

Context

With the original file model up and running, we no longer have a need for the data_file_paths attribute on the Project and Library models.

Problem or idea

All references to data_file_paths should return their corresponding original files.

Solution or next step

There should be a new property method added to the Project and Library models which called original_files, which queries all of a Project or Library's corresponding original files.