[Entity Store] Improve Kibana Tasks Observability (or docs)

[romulets]

Entity Store relies right now in two Kibana tasks:

• Enrich Policy
• Refresh Security data view

And we might rely even more in the near future.

We had two instances of kibana tasks (here and here) silently not working, and debugging hasn't been easy.

We need to improve how we can better observe and debug Kibana Tasks.

Proposed solutions:

• Documentation on how kibana tasks works for our case and where to find logs
  • Include docs on how apiKeys are being generated and kept in SavedObjects
• Information of Kibana Tasks should be available in .kibana indexes. If we can find a way to display in the /app/security/entity_analytics_entity_store configuration page information like last_run would be great.