Adopt new Android-KMP plugin

[vRallev]

https://developer.android.com/kotlin/multiplatform/plugin

I started in a new branch, but some dependencies need to be upgraded first:

• ktfmt: Support com.android.kotlin.multiplatform.library cortinico/ktfmt-gradle#422
• atomicfu: Support com.android.kotlin.multiplatform.library Kotlin/kotlinx-atomicfu#533
• KSP: Support com.android.kotlin.multiplatform.library google/ksp#2476

[vRallev]

Perhaps I should create a separate “android-app” module and not make it KMP compatible, but this isn’t great either.

Yes you should do this. The Android KMP plugin does not support variants because KMP does not and so it's complicated to add it on top of it. But in your app you really need debug vs release to have debuggability and signing control at least. So you need a separate app module.