chore: restructure Linker and Unlinker for system testing

src/Unlinking/Unlinker.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#include "UnlinkerArgs.h"
+
+#include <memory>
+
+class Unlinker
+{
+public:
+    virtual ~Unlinker() = default;
+
+    static std::unique_ptr<Unlinker> Create(UnlinkerArgs args);
+
+    /**
+     * \brief Starts the Unlinker application logic.
+     * \return \c true if the application was successful or \c false if an error occurred.
+     */
+    virtual bool Start() = 0;
+};