audit: Merge ResponseWriter with RecordAPIStats (#9496)

ResponseWriter & RecordAPIStats has similar role, merge them.

This commit will also fix wrong auditing for STS and Web and others
since they are using ResponseWriter instead of the RecordAPIStats.

cmd/http-tracer.go

@@ -123,7 +123,8 @@ func Trace(f http.HandlerFunc, logBody bool, w http.ResponseWriter, r *http.Requ
 	}
 
 	rw := logger.NewResponseWriter(w)
-	rw.LogBody = logBody
+	rw.LogErrBody = true
+	rw.LogAllBody = logBody
 	f(rw, r)
 
 	rq := trace.RequestInfo{