Update Fleet settings for 7.14

[dedemorton]

Summary

Closes elastic/observability-docs#758.

Updates Fleet settings for 7.14.

Checklist

Delete any items that are not applicable to this PR.

• Any text added follows EUI's writing guidelines, uses sentence case text and includes i18n support

[dedemorton]

@jen-huang As a first pass, let's make sure the Kibana docs are complete.

I agree that the disconnect between the Fleet User Guide and Kibana Guide is potentially confusing for users. But I suspect the @elastic/kibana-docs team wants to have all the kibana.yml settings in the same place.

The settings in the Fleet User Guide are exposed in the UI, so I think they need to be described in the Fleet User Guide. If we keep both topics, we should make sure there are links between the topics.

One thing I wasn't quite sure about was precedence. It's possible to set options in kibana.yml, in the elasticsearch output of the agent config, and from the command line. Which settings take precedence?

@Zacqary added you as a reviewer. I have a few questions about some of the descriptions you provided.

[elasticmachine]

Pinging @elastic/fleet (Feature:Fleet)

[gchaps]

LGTM

[dedemorton]

bump. Thanks to Gail for her review, but I still need input from someone on the dev team.

[kpollich]

cc @jen-huang - I think you are probably best suited to answer some of @dedemorton's questions and review these docs.

[jen-huang]

One thing I wasn't quite sure about was precedence. It's possible to set options in kibana.yml, in the elasticsearch output of the agent config, and from the command line. Which settings take precedence?

I think this varies depending on the setting, and not all of these setting are available in all three places.

For xpack.fleet.agents.fleet_server.* and xpack.fleet.agents.elasticsearch.* settings, command line takes precedence, followed by changes in the Fleet UI, and lastly from kibana.yml. (Actually kibana.yml values are ignored once we've populated Fleet settings from them: #105400 (comment))