Avoid eager resolving artifact in CreateDmg#jdkDependency

[vlsi]

mps-gradle-plugin/src/main/groovy/de/itemis/mps/gradle/CreateDmg.groovy

Lines 55 to 60 in a4a8f3c

	Dependency dep = project.dependencies.create(jdkDependency)
	def files = project.configurations.detachedConfiguration(dep).resolve()
	if (files.size() != 1) {
	throw new GradleException(
	"Expected a single file for jdkDependency '$jdkDependency', got ${files.size()} files")
	}

Gradle tasks should not perform artifact resolution at the configuration time as the task might even be non-required at all.

[vlsi]

Oh, it looks like the eager resolution is caused by the fact that the task wants to store File jdk property:

mps-gradle-plugin/src/main/groovy/de/itemis/mps/gradle/CreateDmg.groovy

Lines 19 to 20 in a4a8f3c

	@InputFile
	File jdk

I guess it would make sense to use Property<File> (or RegularFile) API.

[vlsi]

What do you think if CreateDmg task (and the relevant others) were updated to use Property<...> APIs?

What do you think if the task was converted to Kotlin?