Switch to OpenSearch
We are using ES6 which is the last version before ES changed it's licensing model. The open source version was forked into OpenSearch.
In this ticket we replace ES with OS.
I think it makes sense to first upgrade ES libs in our project to the version mentioned in OS migration guide at https://opensearch.org/docs/latest/upgrade-to/upgrade-to/ and then switch over to OS.
The reason for first upgrading ES and then switching to OpenSearch in stages is that we can also slowly migrate our ES cluster.
We now have some custom code for serializing entities for indexing. That code will eventually be removed and replaced with DTO-style mapping to a distinct type before sending it over to ES/OS.