Upgrade to Bevy v0.12 (#12)

* Migrate `System::pipe(...)` calls to `System::map(...)`
* Migrate `EventReader::iter()` and `EventReader::into_iter()` calls to
  `EventReader::read()`
* Migrate asset handling
* Generate `*.meta` files for assets
* Migrate a shader import
* Fix emissive materials double-applying their emissive strength
* Fix non-normalized bone weights resulting in incorrect vertex positions
* Set shadow filtering to `Hardware2x2` to mitigate increase in shader
  compilation times

Cargo.toml

@@ -1,12 +1,9 @@
 [workspace]
 resolver = "2"
-members = [
-    "./bevy_mod_outline",
-    "./studio"
-]
+members = ["./studio"]
 
 [workspace.dependencies.bevy]
-version = "0.11.3"
+version = "0.12.0"
 features = ["tonemapping_luts"]
 
 [profile.dev-custom]