docs: add plugin setup guide

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

@@ -0,0 +1,19 @@
+#pragma once
+
+namespace RE
+{
+	class AITimer
+	{
+	public:
+		static float fTimer()
+		{
+			static REL::Relocation<float*> singleton{ ID::AITimer::fTimer };
+			return *singleton;
+		}
+
+		// members
+		float startTime;   // 00
+		float targetTime;  // 04
+	};
+	static_assert(sizeof(AITimer) == 0x8);
+}