Include javadoc & groovydoc in the same jar and restore source inclusion

Author: jdaugherty

gradle/java-config.gradle

@@ -1 +1,13 @@
-compileJava.options.release = javaVersion.toInteger()
+compileJava.options.release = javaVersion.toInteger()
+
+java {
+    withSourcesJar()
+    withJavadocJar()
+}
+
+tasks.named('javadocJar', Jar).configure {
+    dependsOn tasks.groovydoc
+
+    duplicatesStrategy = DuplicatesStrategy.INCLUDE
+    from tasks.groovydoc.outputs
+}