Add `GetComponent(type)` and `GetBehaviour(type)` to the Actor Lua bindings

[Gopmyc]

Problem this feature should fix

The current Actor Lua API exposes many hardcoded getters (GetCamera, GetLight, etc.) and GetBehaviour(name), but there is no generic lookup by type. This makes scripts more verbose, less scalable, and harder to write in a data-driven way when the component/behaviour type is only known at runtime.

Expected solution

Add two generic Actor bindings in Lua:

• GetComponent(type)
• GetBehaviour(type)

Both should resolve from a type identifier and return the matching instance, or nil when not found. Existing explicit getters should remain supported for backward compatibility.

[Related to #689]