Figure out a way to create Index State Management policies using terraform

[razvan-moj]

Background

To save costs but store more data, we removed the curator (https://github.com/ministryofjustice/cloud-platform-infrastructure/pull/1843) and used a policy similar to https://github.com/ministryofjustice/cloud-platform-terraform-elasticsearch/blob/cold/ism-policy.tpl.json The policy is now applied manually and only visible by going to Kibana.

Approach

Test a provider like https://registry.terraform.io/providers/disaster37/elasticsearch/latest/docs/resources/elasticsearch_index_lifecycle_policy; others are available, none "official".

If nothing works, update the runbooks to mention a workaround.

Definition of done

• [ ] runbook updated
• [ ] tf code in infrastructure updated
• [ ] another team member has reviewed
• [ ] smoke tests are green