Experimental opt-in Kotlin lazy property assignment

[asodja]

Kotlin DSL currently doesn't support an assignment for type Property as Groovy, but .set(T) have to be used. The goal is, that for types with inputs of type Property<T> we support =. This will ease the migration to Provider API for existing scripts and make the use of Provider API for new scripts more compelling.

Example Types:

public interface Extension {
    Property<String> getDescription();
}
public interface OtherExtension {
    Property<String> getDescription();
}

Current DSL:

extension {
    description.set("value")
    description.set(otherExtension.description)
}

New DSL (.set(T) will still work):

extension {
    description = "value"
    description = otherExtension.description
}

In 8.1. we will introduce opt-in Kotlin lazy property assignment.

Related issue:

• https://github.com/gradle/gradle/issues/9268