Creating this epic as a parent task for the Mutualized Opensearch Cluster, a shared Opensearch cluster for light-to-medium production use cases.

AC:

• Mutualized opensearch service is in production
• All non-search-related indices currently on the production Elastic cluster are migrated.
• Any other indices requested by WMF stakeholders are active on the new cluster*

* assuming they meet the requirements as described in the design doc