### Description

Clusters can have thousands of ILM policies. 
`GET _ilm/policy` returns all of them and runs on the master node.

This proposes we chunk the response for better memory usage and clients experience.

Relates to https://github.com/elastic/elasticsearch/issues/96568
x-pack/plugin/ilm/src/main/java/org/elasticsearch/xpack/ilm/action/RestGetLifecycleAction.java
/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the Elastic License
 * 2.0; you may not use this file except in compliance with the Elastic License
 * 2.0.
 */
package org.elasticsearch.xpack.ilm.action;
import org.elasticsearch.client.internal.node.NodeClient;
import org.elasticsearch.common.Strings;
import org.elasticsearch.rest.BaseRestHandler;
import org.elasticsearch.rest.RestRequest;
import org.elasticsearch.rest.action.RestCancellableNodeClient;
import org.elasticsearch.rest.action.RestToXContentListener;
import org.elasticsearch.xpack.core.ilm.action.GetLifecycleAction;
import java.util.List;
import static org.elasticsearch.rest.RestRequest.Method.GET;
public class RestGetLifecycleAction extends BaseRestHandler {