possibility to set "dataset" field on custom Journald

[chicco27]

As for custom logs integration would be useful to have the possibility to set the dataset field for the journald integration

[elasticmachine]

Pinging @elastic/security-external-integrations (Team:Security-External Integrations)

[botelastic]

Hi! We just realized that we haven't looked into this issue in a while. We're sorry! We're labeling this issue as Stale to make it hit our filters and make sure we get back to it as soon as possible. In the meantime, it'd be extremely helpful if you could take a look at it as well and confirm its relevance. A simple comment with a nice emoji will be enough :+1. Thank you for your contribution!