Outdated Documentation (Injector)

There is outdated documentation on the usage of the injector at
https://korlibs.soywiz.com/korge/basics/
and
https://korlibs.soywiz.com/korge/scene/
and the Scenes sample at
https://korlibs.soywiz.com/korge/samples/

The code in question is
```kt
override suspend fun init(injector: AsyncInjector): Unit = injector.run {
mapInstance(MyDependency("HELLO WORLD"))
mapPrototype { MyScene(get()) }
}
```
where the overriden method `init` is deprecated.

I'm am not sure fully sure where to setup the injector.
Please update its intended usage and let me know. Thank you!

Review the injector sections at the basics, scene, and samples URLs, starting with the shown Kotlin example and its deprecated init method. Determine the intended injector setup from the current documentation and update those pages and the Scenes sample so they consistently describe the supported usage without relying on the deprecated method.

Written by the indexing model from the issue text.