Cleanup on 20230308

[danielzgtg]

This PR addresses feedback discussed in the chat, and prepares for the next sprint:

• Explain the axis aligned bounding box logic
• Simplify the depthFirstSearch property into a local
• Remove some leftover debugging
• Put the viewmodel operations in a class for readability, and move the cache variables there as well
• Generalize the DisplayLayer to MyDrawer callback into a proper DisplayLayerHandle class
• Add stubs to allow multiple people to work on things at the same time
  • Add add note button stubs
  • Add completion feature stubs, mostly for part 1