Drop support for auto-configuring an embedded Elasticsearch node

Elastic have announced [1] that embedded Elasticsearch is no longer
supported. This commit brings us into line with that announcement by
removing the auto-configuration that would create an Elasticsearch
Node and NodeClient.

To use the Elasticsearch auto-configuration, a user must now provide
the address of one or more cluster nodes
(via the spring.elastisearch.cluster-nodes property) which will then
be used to create a TransportClient.

See gh-9374

[1] https://www.elastic.co/blog/elasticsearch-the-server

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/autoconfigure/HealthIndicatorAutoConfigurationTests.java

@@ -441,7 +441,7 @@ public class HealthIndicatorAutoConfigurationTests {
 	@Test
 	public void elasticsearchHealthIndicator() {
 		TestPropertyValues
-				.of("spring.data.elasticsearch.properties.path.home:target",
+				.of("spring.data.elasticsearch.cluster-nodes:localhost:0",
 						"management.health.diskspace.enabled:false")
 				.applyTo(this.context);
 		this.context.register(JestClientConfiguration.class, JestAutoConfiguration.class,