Add x-ray tracing to tag-page-rendering

[jorgeazevedo]

What does this change?

This implements request tracing in tag-page-rendering. There quite a number of technical aspects to review, but broadly the idea is

• Make this safe to merge by not modifying the main express server, as this is used by ec2. Instead, we use the otel auto instrumentation, which works by injecting some javascript that runs before the main express server (TODO: is this still true now that it's using new OpenTelemetryWebpackPlugin at build time ?)
• Have the traces be available locally (via Jaeger) and on AWS (via X-ray )

Jaeger screenshot

X-ray screenshot (see it in AWS)

Architecture

OTEL (OpenTelemetry)

While there is an AWS X-ray SDK to post traces directly to the service, I believe it's been deprecated in favour of using OTEL. OTEL Is also a good match as it decouples the collection of traces from the services they end up in. The application posts the traces to http://localhost:4318, which in AWS is an x-ray sidecar that forwards them to x-ray, but locally is a Jaeger container that stores the data and makes available via a web UI.

Auto instrumentation

TODO: how we inject the javascript. And how auto instrumentation doesn't support webpack, so this PR uses a community plugin to get it to work

Jaeger

Jaeger is an open-source tracing platform. We use the official container

X-ray

TODO: The implementation is based on the official AWS otel collector container. I found documentation to be quite sparse, so I had copilot help write it and set it up with a default configuration file that's bundled with the container and does what we want, but I'm not super familiar with this aspect of it yet. The end result is similar to the one in this aws page.

Why?

How has this change been tested?

Screenshots

Before	After

[github-actions]

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From guardian/actions-riff-raff.