Attempt to keep Kotlin totally off the classpath (#1558)

* Attempt to keep Kotlin totally off the classpath

* Add version header for new class

* Fix a few bugs with the samples and provide better debugging output for javaexec

* Use main consistently

* Fix Gradle's published pom and use maven-publish plugin consistently throughout plugin and samples

* Re-add groovydoc jar

* Have assemble create the groovydoc jar

* Switch to publishToMavenLocal

* Sync dependencies with pom.xml and fix null provider for Gradle versions less than 6.2

* Perform quoting conditionally for Windows only

* Add jsch, aether, and shaded libraries to round out compatibility

* Ensure contract tests are generated before kotlin compile task

samples/standalone/restdocs/http-server/src/test/java/com/example/fraud/StubGeneratorTests.java

@@ -40,7 +40,7 @@ import static org.springframework.restdocs.mockmvc.MockMvcRestDocumentation.docu
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
 
 @SpringBootTest(classes = Application.class)
-@AutoConfigureRestDocs
+@AutoConfigureRestDocs(outputDir = "target/snippets")
 @AutoConfigureMockMvc
 @AutoConfigureJsonTesters
 public class StubGeneratorTests {