Add support for Android Foreground Services

https://developer.android.com/guide/components/services
https://developer.android.com/guide/components/foreground-services
https://developer.android.com/about/versions/oreo/background
https://github.com/rust-windowing/android-ndk-rs/issues/128
https://doc.qt.io/qt-5/android-services.html
https://groups.google.com/g/android-ndk/c/bPJG7sRJLcI?pli=1
https://github.com/gburca/BinderDemo

We will need to make it part of the `Plugin` system of `crossbow`. Add option to write `java` files, compile it with `javac`, and link it after stage `rust_compile`.