code: function initGetOneReadMe(router, adminCGIBase, pluginName, handlerNameField, callback) {
      router.get(`${adminCGIBase}/${pluginName}/:${handlerNameField}/readme`, callback);
  }
docs: 获得指定的 handler 的 readme 信息
  @param router
  @param adminCGIBase
  @param pluginName
  @param handlerNameField
  @param callback