docs: add plugin setup guide

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

@@ -0,0 +1,19 @@
+#pragma once
+
+namespace RE
+{
+	class BSSemaphoreBase
+	{
+	public:
+		// members
+		void* semaphore;  // 00
+	};
+	static_assert(sizeof(BSSemaphoreBase) == 0x08);
+
+	class BSSemaphore :
+		public BSSemaphoreBase
+	{
+	public:
+	};
+	static_assert(sizeof(BSSemaphore) == 0x08);
+}