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
