v2.0.0

• Complete rewrite of the plugin in Kotlin and using modern Gradle constructs.
• The plugin now automatically extends each SourceSet and is now largely configurable using these extension properties and a few dependency configurations. The XjcGenerate task still exists under the hood, but will rarely need to be touched from build scripts.
• Allow working with multiple versions of XJC thanks to Gradle's worker API and classpath isolation
• Added a lot of samples and integration tests