New integration for Chrony

[naoyukiseki]

What does this PR do?

This PR adds a new integration for chrony.

Motivation

Chrony is a widely used time‑synchronization tool. Having a Datadog integration for it would be very useful.

Review checklist

• PR has a meaningful title or PR has the no-changelog label attached
• Feature or bugfix has tests
• Git history is clean
• If PR impacts documentation, docs team has been notified or an issue has been opened on the documentation repo
• If this PR includes a log pipeline, please add a description describing the remappers and processors.

Additional Notes

Anything else we should know when reviewing?

[naoyukiseki]

The validate-owner-validator check was failed. But I am a Datadog employee, I believe it can be ignored.
https://github.com/DataDog/integrations-extras/pull/2943/checks?check_run_id=68693094502
Owner is a required internal-only field. Use a valid internal team handle. External contributors should leave this unset.

If I unset the CODEOWNERS, the gh-worker-mergegate-4580a3 / devflow/mergegate was failed.
https://github.com/DataDog/integrations-extras/pull/2943/checks?check_run_id=68691500644

[maycmlee]

Created DOCS-13854 for review.

[github-actions]

This pull request has not been updated for more than 21 days. If there are no updates to this PR within 7 days, it will be closed. If you'd like to re-open this PR after it's been closed, you can start from the latest master branch or pull the latest changes into your branch and create a new pull request.