docs(platform): add package docs to android and ios device prep

internal/android/android.go

@@ -1,3 +1,4 @@
+// Package android boots and prepares an Android device or emulator for testing via adb.
 package android
 
 import (

internal/ios/ios.go

@@ -1,3 +1,4 @@
+// Package ios boots and prepares an iOS simulator for testing via simctl.
 package ios
 
 import (