As a user, I want to import a JSON file so that I may re-use and/or re-configure an existing pipeline.
1. User clicks 'Import' button on Menu.
2. Modal Import window opens.
3a. User may drag/drop a JSON file to designated area.
3b. File icon and name appears in drag/drop area.
4a. User may browse for a JSON.
4b. Browse window opens.
4c. File icon and name appears in drag/drop area.
5. User may enter URL for JSON file.
6. User clicks "Import" button.
7. User may "Cancel" interaction and return to previous screen.
8. Pipeline appears on Canvas.
Note: additional functionality for 3.5