create a request validator engine

src/config.ts

@@ -69,10 +69,7 @@ addDefaults(config, {
             message: "OK",
         }
     },
-    validityCheck: {
-        userAgent: null,
-        userAgentR: null,
-    },
+    requestValidatorRules: [],
     userCounterURL: null,
     userCounterRatio: 10,
     newLeafURLs: null,
@@ -276,4 +273,4 @@ function loadFromEnv(config: SBSConfig, prefix = "") {
             }
         }
     }
-}
+}