Add user scripting module.

[ctrlaltdavid]

• One thread per script, uses Web Workers
• Script Engines / Contexts
  • System (local, non-sandboxed script)
  • User (local script)
  • Avatar (avatar entity)
  • Entity (domain entity)
• API
  • Namespaces
    • CORE (all engines, e.g. scale entities, add materials like shaders)
    • EXTEND (most engines, e.g. raytracing)
    • SPECIFIC (specific features for each engine, e.g. Lumen on UE5)
• Versioning
  • Scripts
• Extensibility
  • App developers may want to add modules to the scripting API.
• Security
  • Isolated from App
  • Isolated from SDK
  • Isolated from Browser in general
  • Isolation is optional and can be broken if desired for full control scripts? ?system vs user script)

Consider this in architecture: https://github.com/Tencent/puerts