- Update the Benchmark JS/Wasm/Native source generation tasks to use the Worker API, so that `kotlin-compiler-embeddable` can be a compileOnly dependency, thus resolving https://youtrack.jetbrains.com/issue/KT-66764
- Create `GenerateJsSourceWorker` and `GenerateWasmSourceWorker` for isolating the JS and Wasm generation code.
- Updated the Js/Wasm/Native generation tasks to invoke the source generators in a Worker isolated classpath.
- Created a new Configuration for declaring `kotlin-compiler-embeddable`, and pass it to the Js/Wasm/Native generation tasks.
- Create a BenchmarkDependencies utility for defining all Configurations used in the plugin. (This also lays the groundwork for unifying the JMH version #147 (comment))
- Updated BenchmarksPluginConstants to add `DEFAULT_KOTLIN_COMPILER_VERSION`, as sensible default for kotlin-compiler-embeddable.
- Add opt-in annotation RequiresKotlinCompilerEmbeddable to highlight code that requires `kotlin-compiler-embeddable`
- Some classes were updated to be `abstract`, to follow Gradle best practices for creating managed objects.

This commit also contains formatting changes, as the code style is not consistent.