Kotlin DSL

### The documentation URL

https://jmeter.apache.org/usermanual/build-programmatic-test-plan.html

### Feedback

Missing info of hot to actually run created test plan.
It would be nice to have a working project with most basics covered, e.g. how can one configure path to results log is also not obvious (btw Java DSL seems to cover its relevant API (`jtlWriter("target/jtls")`) in documentation, but I'd prefer to work with Kotlin, though cannot find any documentation)

Also it is not cleat how can one reference existing tree elements (typesafe refs in ModuleController maybe with support of refactoring of pointed elements in-tree location)

Also so far I wasn't able to make jmeter functions like `__groovy` work in lets lay `HTTPSamplerProxy` fields, not sure what I'm missing.