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

src/ObjLoading/Parsing/StructuredDataDef/StructuredDataDefReader.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "Domain/CommonStructuredDataDef.h"
+#include "Parsing/IParserLineStream.h"
+
+class StructuredDataDefReader
+{
+public:
+    using include_callback_t = std::function<std::unique_ptr<std::istream>(const std::string& filename, const std::string& sourceFile)>;
+
+private:
+    std::string m_file_name;
+    IParserLineStream* m_stream;
+    std::vector<std::unique_ptr<IParserLineStream>> m_open_streams;
+
+    bool OpenBaseStream(std::istream& stream, include_callback_t includeCallback);
+    void SetupStreamProxies();
+
+public:
+    StructuredDataDefReader(std::istream& stream, std::string fileName);
+    StructuredDataDefReader(std::istream& stream, std::string fileName, include_callback_t includeCallback);
+
+    std::vector<std::unique_ptr<CommonStructuredDataDef>> ReadStructureDataDefs();
+};