[DON-2261] Migrate Gradle build scripts from Groovy to Kotlin DSL#2532

RichSutherSky wants to merge 2 commits intomainSkyscanner/backpack-android:mainfrom

donburi/DON-2261-android-backpack-migrate-to-kotlin-gradle-scripts-from-groovy-to-align-with-appSkyscanner/backpack-android:donburi/DON-2261-android-backpack-migrate-to-kotlin-gradle-scripts-from-groovy-to-align-with-appCopy head branch name to clipboard