Capture FQDN for host name

[SylvainJuge]

What does this PR do?

Fixes #3131

Relies on the still work-in-progress specification PR: elastic/apm#805

Checklist

• This is an enhancement of existing features, or a new feature in existing plugins
  • I have updated CHANGELOG.asciidoc
  • I have added tests that prove my fix is effective or that my feature works
  • Added an API method or config option? Document in which version this will be introduced
  • I have made corresponding changes to the documentation

[apmmachine]

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Build stats

• Start Time: 2023-07-03T11:39:17.169+0000

• Duration: 14 min 2 sec

❕ Flaky test report

No test was executed to be analysed.

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