docs: add plugin setup guide

plugin/lib/commonlibf4/include/RE/P/PackageSchedule.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#include "RE/P/PACK_SCHED_DATA.h"
+
+namespace RE
+{
+	class PackageSchedule
+	{
+	public:
+		// members
+		PACK_SCHED_DATA psData;  // 0
+	};
+	static_assert(sizeof(PackageSchedule) == 0xC);
+}