[Enhancement] PPL Alerting: AlertV2 expiration and movement should be batched

[toepkerd]

Is your feature request related to a problem?
Currently, when AlertV2Mover logic sweeps for expired alerts, copies expired ones to alert v2 history indices, and then deletes the existing alerts from the active alerts v2 indices, they are all done with single bulk requests. If alerts are numerous or voluminous, this may cause performance issues.

What solution would you like?
Refactor the copy and delete logic to batch the alert document copy and delete requests.

[andrross]

Catch All Triage - 1 2 3