Is your feature request related to a problem? Please describe.
TransportClient.java is deprecated and should be removed and adopt using High Level Rest Client.

https://github.com/opensearch-project/OpenSearch/blob/main/server/src/main/java/org/opensearch/client/transport/TransportClient.java

There are a lot of references where TransportClient is used, all of the uses cases should be moved a layer above of TCP to Rest (Layer 7).

The intent of this issue is to sanitizing the code base.