Module Editor: Reordering lessons

[draymond63]

Summary

We will want to add the ability to reorder the lessons via drag & drop. When the user hovers over a lesson in the module editor sidebar a drag handle will appear. Then, if the user drags this handle, the lessons will be rearranged. We will use the same library as we do for the rearranging of the lesson content, which is react-beautiful-dnd.

Goals

• Drag and drop of lessons within the SideBarModuleOverview
• Dragging the lessons results in an update of the state

Implementation

Follow the design in the LessonViewer for guidance. Message @draymond63, because he's done this before :)

[mslwang]

Paused development for now.