apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/api/AdminServiceAPI.java/ClusterAPI/delete
class ClusterAPI:    public void delete(Env env, String appId, String clusterName, String operator) {
      restTemplate.delete(env, "apps/{appId}/clusters/{clusterName}?operator={operator}", appId, clusterName, operator);
    }