Add tracing plugin for undici/fetch

[hansott]

Hi Sentry team! 👋

nodejs/node#41749 has just been merged (adds fetch to Node.js).

The default tracing plugin that ships with the SDK adds a span for each HTTP request of the http/https modules from node.

This is great but we've been using undici for a while now and added manual instrumentation for it.

The newly merged fetch builds on top of undici.

Would be great if there was tracing support built-in for undici/fetch.

Thanks!

[AbhiPrasad]

Awesome to see fetch finally land :)

We'll add this to the backlog to work on, but PRs are welcome for anyone who wants to help out!