Update container log file example

[JacksonDavenport]

trafficstars

What does this PR do?

Update the example where you can collect logs from a log file within another application container. The current log sample used a "dummy" container, the new sample can be actually deployed to create these logs in a way that the Agent can access them. So a much more "real" example a customer can follow.

Additionally changes the formatting a bit to better highlight requirements of this, rather than including them as bullet point notes.

Motivation

Clear up the example

Preview

https://docs-staging.datadoghq.com/jack.davenport/k8s-logs/containers/kubernetes/log/?tab=daemonset#examples---log-collection-from-file-configured-in-an-annotation

Current:

• https://docs.datadoghq.com/containers/kubernetes/log/?tab=daemonset#examples---log-collection-from-file-configured-in-an-annotation

Additional Notes

---

Reviewer checklist

• [ ] Review the changed files.
• [ ] Review the URLs listed in the Preview section.
• [ ] Check images for PII
• [ ] Review any mentions of "Contact Datadog support" for internal support documentation.

[github-actions[bot]]

Preview links (active after the build_preview check completes)

Modified Files

• https://docs-staging.datadoghq.com/jack.davenport/k8s-logs/containers/kubernetes/log

[maycmlee]

Created DOCS-3939 for review.