Add config for server.keepAliveTimeout

lib/config.ts

@@ -48,6 +48,7 @@ const options = {
   CWMP_SSL_KEY: { type: "string", default: "" },
   CWMP_LOG_FILE: { type: "path", default: "" },
   CWMP_ACCESS_LOG_FILE: { type: "path", default: "" },
+  CWMP_KEEP_ALIVE_TIMEOUT: { type: "int", default: 0 },
 
   NBI_WORKER_PROCESSES: { type: "int", default: 0 },
   NBI_PORT: { type: "int", default: 7557 },