docs: add plugin setup guide

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

@@ -0,0 +1,20 @@
+#pragma once
+
+namespace RE
+{
+	class BSISoundDescriptor;
+
+	class BSAudioCallbacks
+	{
+	public:
+		using IDCallback_t = bool (*)(std::uint32_t, const BSISoundDescriptor**);
+		using NameCallback_t = bool (*)(const char*, const BSISoundDescriptor**);
+		using PostProcessCallback_t = void (*)();
+
+		// members
+		IDCallback_t          idCallback;           // 00
+		NameCallback_t        nameCallback;         // 08
+		PostProcessCallback_t postProcessCallback;  // 10
+	};
+	static_assert(sizeof(BSAudioCallbacks) == 0x18);
+}