Port All Android Java App Use Cases to the Kotlin App

[cpholguera]

The MASTG Hacking playground apps differ in functionality. We'd like to keep working on the Kotlin app going forward and for that we need to port everything from the Java app and ensure it works in Kotlin on the latest Android version.

Porting the UI elements should be evaluated but it's possibly not worth the effort. Maybe redoing them using the current Android UI recommendations is more adequate. In the end the screens were very simple.

The code on the Java app is very repetitive (as it is for the UI elements). Please consider optimizing it as much as possible to enable easier creation of new use cases in the future. If possible, create some templates.

The list of test cases is here: https://github.com/OWASP/MASTG-Hacking-Playground/wiki/Android-App