Asset Lifetime v2 - Optimized Scene Transition

Kenix3
- [ ] At game boot load all authentic game assets, load all HD assets that are NOT in overlays/scenes/objects. Load HD gameplay_keep. Load all HD GI objects.
- [ ] Create actor asset load/unload functions for all actors.
- [ ] On scene transition, load all assets necessary for a scene. Since we aren't streaming load rooms for v2, we should probably preload all rooms in the scene.
- [ ] On actor spawn and scene transition for each actor in the scene, load all assets necessary for an actor when it is spawned in. We will need to add a function in SoH's actor struct that loads all of it's necessary assets. Run this when the actor is spawned.
- [ ] When transitioning scenes, unload the appropriate keep (dungeon or field)
- [ ] When all instances of an actor are despawned, we run the actor asset unload function. In the actor asset unload function we unload all of the assets that the actor depends on.