Start adding in-code documentation and add docs generator

[xthexder]

• Add docs/ folder with code-generated ECS components (grouped by category)
• Add scene.schema.json for scene auto completions (VSCode settings updated)
• New sp::json::SaveSchema() and StructMetadata::DefineSchema functions for per-type definitions
• Change all remaining component serializations to be snake_case (e.g. light.spotAngle -> light.spot_angle)
• Rename sound/ecs::Sounds component to audio/ecs::Audio component to make docs less ambiguous.
• Change TrnasformSnapshot to be a struct instead of a Transform typedef to make it's typeid distinct
• Fix bug with console input thread crashing in build
• Build time improvements for the reflection template code