As of Spring Data Moore, the Elasticsearch high level REST client is
supported for Spring Data repositories. The transport client is now
deprecated and is likely to be removed in a future Spring Data release.

This commit deprecates the transport client and marks all the associated
configuration properties as deprecated. The Spring Boot starter depends
on the `spring-data-elasticsearch` project, which now depends on both
transport client and high level REST client.

This commit also deprecates the Jest client, as Spring Boot will focus
on supporting the high level REST client and the reactive client
provided by Spring Data - both being in sync with the fast release pace
of Elasticsearch.

Closes gh-15008