Support new ElasticsearchClient

[bclozel]

As discussed in #28496, we'd like to add dependency management and auto-configuration for the new ElasticsearchClient.
Support for the former RestHighLevelClient will be deprecated as a result.

[wilkinsona]

This will have to wait until Spring Boot 3.0 as the new client uses JSON-B 2.0 which is part of Jakarta EE 9.

[dawi]

But jakarta.json.bind-api is a compileOnly dependency and as such it should only be used during source compilation and it shouldn't be included in the runtime classpath.

[wilkinsona]

I believe that arrangement is because it's optional at runtime and not because it's never used at runtime. That optional dependency is still enough to prevent its use in Spring Boot 2.x where, if JSON-B is used, it must be 1.x with javax.json packages.