docs: add plugin setup guide

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

@@ -0,0 +1,16 @@
+#pragma once
+
+namespace RE
+{
+	class BSStreamHeader
+	{
+	public:
+		// members
+		std::uint32_t version;            // 000
+		char          author[64];         // 004
+		char          processScript[64];  // 044
+		char          exportScript[64];   // 084
+		char          maxFilePath[260];   // 0C4
+	};
+	static_assert(sizeof(BSStreamHeader) == 0x1C8);
+}