Renderer scene and camera improvements

[benreid24]

• [x] Add createDefaultCamera pure virtual to BatchedScene
• [x] Create 2d scene inherited from BatchedScene and set default camera to 2d camera
• [x] Create 3d scene and set default camera to 3d camera
• [x] Remove default camera parameter from build system
• Replace 2d camera viewport with zoom factor
  • Make 2d camera aware of VkViewport
  • Add zoom helper for camera to show desired world region
  • Allow extra zoom factor to be applied to world region size for ease of use
  • Also allow manual setting of zoom
• [x] Replace raw scene pointers with scene handle
• [x] Implement reference counting of scene handles and clean up dangling scenes automatically in ScenePool
• [x] Replace TextSyncSystem with tasks issued from Text
  • [x] Task adding should return handle that can be used to check and cancel task
• [x] Move default near/far plane values into Scene instead of renderer/observer
• [x] Allow overlays to work in arbitrary coordinate space instead of only normalized
• [x] Update OverlayScalerSystem to support arbitrary overlay sizes
• [x] Add helper method to existing drawables to scale to a specific size