[Actionable Observability] Create service to ensure correct index setup

[kdelemme]

📝 Summary

Part of #137323

When we create an SLO, the route handler will make sure the destination index used by the transformer exists and is correctly setup.
If not, we need to create the component template mappings, component template settings and index templates for the destination index.

The destination index will be named as follow: slo-data-[SLO-ID]

📣 At the moment, we are considering using one destination index per slo definition. Meaning, every transformers will write into their own index. So this index needs to be setup correctly before we start writing into it.

✅ Acceptance Criteria

• The service creates all the necessary index settings, mappings and templates (very similar to Chris' POC) when not defined yet
• The service returns early if everything exists

[elasticmachine]

Pinging @elastic/actionable-observability (Team: Actionable Observability)