ResourceGroupParser refactor

Stuck with the commented out tests failing.
You are missing `#include "ResourceParser.h" ` **to pull in the partial template specialization** for the `Resource` class in the `Signature.cc` – that is why default `SectionProcessorBase:: sectionType()` is used – `UndefinedSectionType` and the resource section `/r2` is never recognized (and parsed as a description).