Restructure project

* use modules instead of source sets
* Kotlin JVM instead of multiplatform (for now) to make things simpler
* Warning: GameCell doesn't use mutableState anymore, this needs to be
           fixed for the UI to work!

commonUI/src/main/composeResources/drawable/window-minimize.xml

@@ -0,0 +1,10 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="960"
+        android:viewportHeight="960"
+        android:tint="?attr/colorControlNormal">
+    <path
+            android:fillColor="#FFFFFF"
+            android:pathData="M240,840L240,760L720,760L720,840L240,840Z"/>
+</vector>