docs: add plugin setup guide

plugin/lib/commonlibf4/include/RE/A/ACTION_OBJECT.h

@@ -0,0 +1,13 @@
+#pragma once
+
+namespace RE
+{
+	class ACTION_OBJECT
+	{
+	public:
+		// members
+		TESForm*      form;   // 00
+		std::uint32_t flags;  // 08
+	};
+	static_assert(sizeof(ACTION_OBJECT) == 0x10);
+}