[REQUEST]: Enhance/Warn about current limitations of configurable ES outputs

[lucabelluccini]

Description

We should warn about the fact at the moment it is not supported to configure Elasticsearch outputs (both for data & monitoring) which are NOT pointing the cluster to which Fleet Server is configured to connect to.

The UI and Docs might trick the final user into thinking it is possible to route events to any Elasticsearch cluster if credentials are provided.

Credentials would not be enough as to correctly work Fleet Server would also need to set up the assets (both Elasticsearch & Kibana assets).

We should warn users as clearly as possible at https://www.elastic.co/guide/en/fleet/master/fleet-settings.html#es-output-settings. Bonus points if the UI in the product itself warns about it.

Resources

We have an issue to start supporting remote ES clusters (elastic/kibana#104986).

Collaboration

TBD. The docs and product team will work together to determine the best path forward.

Point of contact.

Main contact: @lucabelluccini

Stakeholders: ?