Spring-ai Add support for Elasticsearch vector store

This PR adds supports for Elasticsearch vector search.

To achieve compatibility with both Elasticsearch versions 7 and 8, I implemented it using Elasticsearch's Java Low Level REST Client.

To-do: - [x] Add ElasticsearchAiSearchFilterExpressionConverter - [x] Add support for FilterExpression - [ ] Add support for various vector functions provided by Elasticsearch - [ ] Add autoconfiguration - [ ] Write README

Comment From: JM-Lab

The mix-up in the commit logs. I'll close this PR and submit it again shortly.