FEATURE: Add SCORE Authoring with View Casting

[JoelWiebe]

Feature

Overview
Create a SCORE Authoring page that allows teachers to cast students to canvases. (Casting to canvases is a tentative/intermediary step -- later we will add support for casting to multiple resources to particular groups).

Details
Create a SCORE Authoring page that is only available to teachers. This will have a three pane layout based on the layout structure displayed in issue #469. Tentatively, let's list all canvases across all projects in the left pane with a play button to the right of the canvas name. If clicked, display that tab and canvas of the clicked canvas, dynamically in real-time to all members of the class with the SCORE run open.

Tasks

TODO