QtGP create external JSON and gradle.properties example

Currently Qt Gradle Plugin gets its inputs from QtBuild{} extension.
This extension is defined in app/build.gradle(at least in our current examples), but according to gradle's multi-module structure it could be defined in any other module. This makes it complicated for the Qt Tools for Android Studio(QtTAS) plugin to find. Editing the build.gradle file is also not easy, since there is no documentation/API for modifying the custom extension in kotlin or groovy.

Why

• Because QtGP could be defined anywhere in multi module project structure
• QtTAS will have problems finding and editing the custom extension

There are currently two options we are considering to move from the custom extesion to gradle.properties or json file

gradle.properties

• Already shows up in Android project view pane
• Examples of other plugins using it
• QtGP can read the file without needing a 3rdparty library

JSON

• Firebase plugin is an example of it, but they generate and provide the file with their web console.
  • We could generate the file using QtTAS, but user would still need to do it manually if using only QtGP
• QtTAS can create the file. Unlike gradle.properties file, it won't appear in Android project pane.
• QtGP will need a 3rdparty library to read value from the json file.

Definition of done

When both plugins QtTAS & QtGP can read properties from the same file. QtTAS should also be able to write to this file.