chore: restructure Linker and Unlinker for system testing

src/Unlinking/UnlinkerPaths.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include "SearchPath/SearchPaths.h"
+#include "UnlinkerArgs.h"
+
+#include <string>
+#include <unordered_set>
+
+class UnlinkerPaths
+{
+public:
+    bool LoadUserPaths(const UnlinkerArgs& args);
+    std::unique_ptr<ISearchPath> GetSearchPathsForZone(const std::string& zonePath);
+
+private:
+    std::string m_last_zone_path;
+    SearchPaths m_last_zone_search_paths;
+
+    std::unordered_set<std::string> m_specified_user_paths;
+    SearchPaths m_user_paths;
+};