Add initial draft of structured data def parser to parse enums only for now

src/ObjLoading/Parsing/StructuredDataDef/StructuredDataDefParserState.cpp

@@ -0,0 +1,10 @@
+#include "StructuredDataDefParserState.h"
+
+using namespace sdd;
+
+StructuredDataDefParserState::StructuredDataDefParserState()
+    : m_current_def(nullptr),
+      m_current_enum(nullptr),
+      m_current_struct(nullptr)
+{
+}