Use Kotlin & QuPath Gradle Plugin

[petebankhead]

Updates this repo for QuPath v0.6.0 with two big changes:

• Uses Kotlin DSL with Gradle
• Uses the new QuPath Gradle Plugin

The practical outcome is that the build files can be much shorter and simpler.

[alanocallaghan]

Looks great, hopefully kotlin isn't intimidating for new users (or at least if so, they don't ever have to deal with it)

[petebankhead]

Thanks, this will take a bit longer since it's failing with includeFlat... unless I use includeBuild with the plugin repo... errors are obscure and I am very lost.

[petebankhead]

With regard to intimidatingness, I think it should be much lower now as there are only two blocks that need to be edited - and perhaps the dependencies block, but that's standard Gradle, and Gradle's own docs now show Kotlin instructions more prominently than Groovy.

build.gradle.kts

// TODO: Configure your extension here (please change the defaults!)
 qupathExtension {
     name = "qupath-extension-template"
     group = "io.github.qupath"
     version = "0.1.0-SNAPSHOT"
     description = "A simple QuPath extension"
     automaticModule = "io.github.qupath.extension.template"
 }

settings.gradle.kts

// TODO: Specify which version of QuPath the extension is targeting here
 qupath {
     version = "0.6.0-SNAPSHOT"
 }

[petebankhead]

See qupath/qupath#1709 for more info.

[alanocallaghan]

With regard to intimidatingness, I think it should be much lower now as there are only two blocks that need to be edited - and perhaps the dependencies block, but that's standard Gradle, and Gradle's own docs now show Kotlin instructions more prominently than Groovy.

Rationally I agree, but I feel like sometimes people are unduly put off by different languages. I don't think it's worth stopping useful improvements for though either way

[carlocastoldi]

with this PR, running ./gradlew clean shadowJar -P toolchain=21 fails because it cannot choose between the available variants dependencies for libs.qupath.fxtras :\

[petebankhead]

Thanks @carlocastoldi that should now be fixed (the order the plugins are added at the top of build.gradle.kts is what matters)