Consider replacing `KClass` with custom information class as DSL result

The idea is that WithX.toList should return not a KClass, which assumes further runtime reflection, but an information class storing all the information about the class available to Reflekt plus the old KClass reference.

This is particularly useful to implement #71, because actually KClass has the sealedSubclasses property that does that thing; however, this data can be collected at compile time, and it’s helpful in cases where run-time reflection isn’t available or too slow.

Rough API:

class ReflektClass<T> {
  val kotlin: KClass<T>
  val qualifiledName: String
  val simpleName: String
  val sealedSubclasses: List<ReflektClass<*>>
  val isOpen: Boolean
  ...
}

Possible usage:

Reflekt.classes().withSuperType<B1>().toList().map { /* it: ReflektClass<B1> */ it.qualifiedName }.forEach { println(it) }

Also, to not bloat the ReflektImpl file, there must be a registry of such classes to have them available in many DSL calls simultaneously (basically, val classData: HashMap<String, ReflektClass<*>>).

[nbirillo]

We use KtObjectDeclaration in lamda bodies to access its fields, next we run KotlinScript. In this case, we would like to use our wrappers and don’t use some internal compiler classes

[nbirillo]

Next, we should make the same for objects and functions