Replace ElasticSearch with OpenSearch

[eloiferrer]

Our ElasticSearch index is incomplete. Some indexing jobs fail and it is not straightforward to debug what goes wrong. We also see this warning:

ElasticSearch support is deprecated and will be End-of-Life in the next release. Upgrading to OpenSearch will be required. 

We need to replace ElasticSearch with OpenSearch.

Documentation https://www.mediawiki.org/wiki/MediaWiki-Docker/Configuration_recipes/OpenSearch

[eloiferrer]

I have concluded this in staging:

• Install OpenSearch
• Reindex all data in OpenSearch
• Remove ElasticSearch

[eloiferrer]

Starting now with the reindexing of data to OpenSearch in production