Introduce support for mixed lighting by allowing lights to opt out of

illuminating lightmapped objects.

This should be fully working, but it needs some better documentation and
a little polish on the example, so I'm marking it as a draft for now.

Cargo.toml

@@ -3849,6 +3849,17 @@ description = "Demonstrates percentage-closer soft shadows (PCSS)"
 category = "3D Rendering"
 wasm = false
 
+[[example]]
+name = "mixed_lighting"
+path = "examples/3d/mixed_lighting.rs"
+doc-scrape-examples = true
+
+[package.metadata.example.mixed_lighting]
+name = "Mixed lighting"
+description = "Demonstrates how to combine baked and dynamic lighting"
+category = "3D Rendering"
+wasm = true
+
 [[example]]
 name = "animated_ui"
 path = "examples/animation/animated_ui.rs"