docs: add plugin setup guide

plugin/lib/commonlibf4/include/RE/D/DetectionLevels.h

@@ -0,0 +1,13 @@
+#pragma once
+
+namespace RE
+{
+	class DetectionLevels
+	{
+	public:
+		// members
+		std::int16_t visualLevel;  // 00
+		std::int16_t soundLevel;   // 02
+	};
+	static_assert(sizeof(DetectionLevels) == 0x04);
+}