feat: Add structured logging for requests made to DCR and CAPI

[akash1810]

What does this change?

This change adds a log after making a GET request to CAPI or a POST request to DCR. The log line is structured, with markers covering the URL, response code, content length and request duration. We can use this to monitor the performance of these requests and identify any issues with them.

I've attempted to namespace the markers to distinguish them from the request logs.

For example, in the project to run DCR on ECS, we've been doing some load testing to right-size the ECS cluster.
Whilst doing this, we've noticed the latency of a request is sometimes unexpectedly high.

In guardian/dotcom-rendering#16408, we've added tracing and the results show a significant time is spent reading the POST body and parsing it as JSON.

We've a hypothesis that payload POSTed to DCR is a superset of what it needs (see also #28964 and #27894).
These logs should help us graph the size of the payload and the time taken to read it, so we can see if there's a correlation between the two.

Note

Ideally, we'd log the request-id as a marker too as that would allow us to relate a CAPI log line with a DCR log line. There are some helpers for this, however it requires an implicit headers: RequestHeader which isn't available in ContentApiClient.scala.

I couldn't cleanly satisfy this requirement, so I've left it out for now. My Scala is pretty rusty these days, so any help is most welcomed!

Screenshots

After deploying to CODE, we can see the logs in Central ELK:

Checklist

• Tested locally, and on CODE if necessary
• Will not break dotcom-rendering
• Any new test data/database files generated by tests are committed with this PR (the tests will fail in CI if you've forgotten to do this)
• Meets our accessibility standards
  • Tested with screen reader
  • Navigable with keyboard
  • Colour contrast passed

[github-actions]

Deploy build 7383 of dotcom:frontend-all to CODE

All deployment options

• Deploy build 7383 of dotcom:frontend-all to CODE
• Deploy parts of build 7383 to CODE by previewing it first
• What's on CODE right now?

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From guardian/actions-riff-raff.

[akash1810]

Superseded by #28984. Closing.