Add Docs for build.gradle.kts

[jamesward]

I use build.gradle.kts but the docs only have instructions for the legacy build.gradle definitions. It'd be great if the docs contained info on how to setup things also with build.gradle.kts definitions.

[aalmiray]

Gradle has an specific issue in this regard, there are now 3 DSLs:

• Groovy
• Kotlin
• Declarative Gradle

We already provide all snippets in 5 formats. Adding 2 more is a bit of a daunting task. Besides, IntelliJ offers refactoring options to convert from one format to the other.

[jamesward]

I know. It's a lot. If you only want to do 1 Gradle format I think it should be kts because it will be mostly compatible with the new declarative stuff and is the default for Gradle.