CLC-4603 - Roster Export: As an Instructor, I want to be able to export my course roster

https://jira.ets.berkeley.edu/jira/browse/CLC-4603
@redconfetti do we need this? Can't we use `api.util.printPage()` in the page? All the api functions should be exposed & available in the view: https://github.com/ets-berkeley-edu/calcentral/blob/464bc5d4cd23bbbd5d369f3b625c151dbe9a11fd/app/assets/javascripts/angular/controllers/calcentralController.js#L9