Update structure using new template

[codeanticode]

A while ago, @sarahlensing created a new project template for Android libraries that better follows gradle standards:

https://gitlab.com/sarahlensing/template

It's in the new-template branch:

https://github.com/processing/processing-android-library-template/tree/new-template

Seems like this template could facilitate coding libraries in IntelliJ/Android Studio, it could even be useful as a model for the Android mode/core library themselves.