36732 Flutter build aar

10778 Build JARs containing the Android embedding sources and the engine native library

34573 Ensures flutter jar is added to all build types on plugin projects

36695 Android visible password input type support

36805 Allow flavors and custom build types in host app

37194 [flutter_tool] More gracefully handle Android sdkmanager failure

37405 Add .android/Flutter/flutter.iml to module template.

37752 Remove dead flag gradle-dir in flutter config

9206 Android Embedding Refactor PR31: Integrate platform views with the new embedding and the plugin shim.

9360 Simplify loading of app bundles on Android

9476 fix NPE when a touch event is sent to an unknown Android platform view