docs: add plugin setup guide

plugin/lib/commonlibf4/include/RE/B/BSScaleformExternalTexture.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#include "RE/B/BSFixedString.h"
+#include "RE/N/NiPointer.h"
+
+namespace RE
+{
+	class NiTexture;
+
+	class BSScaleformExternalTexture
+	{
+	public:
+		// members
+		NiPointer<NiTexture> gamebryoTexture;  // 00
+		std::uint32_t        renderTarget;     // 08
+		BSFixedString        texturePath;      // 10
+	};
+	static_assert(sizeof(BSScaleformExternalTexture) == 0x18);
+}