Add reference to ExceptionHandler in HandlerResult

It will be useful if `HandlerResult` will contains reference to parent `ExceptionHandler` that allow to create useful extension like `next` to build chains:

```
val lastExecutionResult = exceptionHandler.handle {
    repository.request1()
}.execute()
.next {
    repository.request2()
}.catch<IllegalStateException> {
    false
}.execute()
```