Instrument `fetch` and other improvements

Instrument calls to fetch in Node.js. Requests made using Node.js' global fetch, or through the underlying undici library, will be automatically instrumented and shown as events in your performance samples' event timeline.

Support Kamal-based deployments. Read the KAMAL_VERSION environment variable, which Kamal exposes within the deployed container, if present, and use it as the application revision if it is not set. This will automatically report deploy markers for applications using Kamal.

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See the Node.js package 3.4.4 changelog for more information.