migrate to new elasticsearch java client for es > 7.16

High Level Client is depracated, instead use:

• https://github.com/elastic/elasticsearch-java
• https://www.elastic.co/docs/reference/elasticsearch/clients/java

Notes for migration:

• The High Level Client version 7.16 and higher can communicate with Elasticsearch version 8.x after enabling API compatibility mode. -> https://www.elastic.co/guide/en/elasticsearch/client/java-rest/current/java-rest-high-compatibility.html
• When compatibility mode is enabled, the client can also communicate with Elasticsearch version 7.11 and higher.
• Migration: using both side by side is possible: https://www.elastic.co/guide/en/elasticsearch/client/java-api-client/7.16/migrate-hlrc.html

This means elasticsearch shall be running on version 7.11, 7.16 or 8 before client migration?