migrate next to opensearch

[drjova]

OpenSearch, it's already connected to QA we have to do the following steps:

• [ ] [QA] test reidex/remapping cli https://inspire.docs.cern.ch/operations/holdingpen/#holdingpen
• [ ] copy the PROD indices from ES to OS cluster using the reindex API
• [ ] stop harvesting
• [ ] update config on next to connect to the new cluster
• [ ] reindex
• [ ] star harvesting
• [ ] check that everything is ok