[TASK] Modify ReindexThread/ContentletIndexAPI to accomplish DUAL write

[fabrizzio-dotCMS]

Description

include all the changes in the ContentletIndexAPI to accomplish DUAL WRITE
Focus on the methods used by ReindexThread, that use a BulkProcessor

Acceptance Criteria

• [] Upon feature flag activation, we should be able to replicate asynchronously the writes performed to ES without impacting regular operation

Priority

None

Additional Context

No response