[Backport 2.x] [Tiered caching] Introducing cache plugins and exposing Ehcache as one of the pluggable disk cache option#12514

peternied merged 2 commits intoopensearch-project:2.xopensearch-project/OpenSearch:2.xfrom

sgup432:backport-11874-to-2.xsgup432/OpenSearch:backport-11874-to-2.xCopy head branch name to clipboard