Document Logstash output in Agent

[mostlyjason]

Document how users can set the Logstash output in the standalone agent policy elastic/beats#24020

[dedemorton]

Starting this work now. I'm going to add the Logstash settings to the PR that's started here: #460

[dedemorton]

@mostlyjason Can you paste in an example logstash config into this issue? I usually start by looking at the reference yaml, but I don't see anything there for logstash: https://github.com/elastic/beats/blob/master/x-pack/elastic-agent/elastic-agent.reference.yml

[mostlyjason]

@nimarezainia this is agent standalone so I think you own this one? Maybe PH left an example somewhere here or in the linked issues elastic/beats#24020?

[dedemorton]

BTW, Andres has asked @faec to help me with this.

[nimarezainia]

@nimarezainia this is agent standalone so I think you own this one? Maybe PH left an example somewhere here or in the linked issues elastic/beats#24020?

@mostlyjason no don;t have this but I can try and get it. Will revert back.

[dedemorton]

Closed by #904.

We also have a more detailed PR in progress to add all the settings: #460