Kotlin version of app demo

[Pertence]

Checklist

• [x] I read the Contribution Guidelines
• [ ] I signed the CLA and WG Agreements
• [x] I ran, updated and added unit tests as necessary.
• [x] I verified the contribution matches existing coding style.
• [ ] I updated the documentation if necessary.

Motivation and Context

Kotlin is an officially supported language for Android app development but, there is only a Java version of the demo. With the Android Studio, it is possible to automatically convert the Java code, but the resulting code needs additional work to compile and run correctly. This commit cuts the step to convert Java to Kotlin every time someone wants to have a Kotlin version.

Description

This commit adds a Kotlin version of the demo app based on the Java version. It also uses view binding. However, it does not have the browser selection feature because replacing AsyncTask with Kotlin Coroutines is nontrivial.