[Logstash] Docs: Update data resiliency page/section to reference ES failure store

[karenzone]

Logstash page: https://www.elastic.co/docs/reference/logstash/queues-data-resiliency
Elasticsearch page: https://www.elastic.co/docs/manage-data/data-store/data-streams/failure-store

The Elasticsearch failure store (9.1 and later) for data streams offers Logstash users another alternative for handling events that can't be processed. Logstash offers the Dead Letter Queue (DLQ), but the failure store will likely be a more practical option for Elasticsearch users.

Also:

• Add content to Logstash release notes for existing users who spin up a new instance and see different behavior
• Troubleshooting content: ("Where'd my data go???")
• SDH planning and resources

[karenzone]

@robbavey, please add this docs issue to your meta issue. We can add Failure store to Logstash docs now, and continue to iterate as our DLQ strategy develops.