feat: implement net.fetch

[nornagon]

Description of Change

This implements net.fetch(), by analogy to fetch() on the Web and fetch()
in Node, but using Chromium's network stack.

Checklist

• PR description included and stakeholders cc'd
• npm test passes
• tests are changed or added
• relevant documentation, tutorials, templates and examples are changed or added
• PR release notes describe the change in a way relevant to app developers, and are capitalized, punctuated, and past tense.

Release Notes

Notes: Added net.fetch().

[nornagon]

Alrighty, I've been running this implementation against the Web Platform Tests (WPT) via a hacked-up version of undici's test harness, and it's doing pretty good so far:

[fetch]: Completed: 900, failed: 178, success: 722, expected failures: 139, unexpected failures: 39, skipped: 7

the remaining "unexpected failures" are:

• when we reject a body promise due to an abort signal, it doesn't get rejected until after the next microtask. this is because our body stream rejection goes through a Node.js stream close, which emits on nextTick. This seems like an okay bug to ship with, I think.
• Response.type is returning 'default' instead of 'basic' in many cases. This isn't fixable without patching undici, since it doesn't allow setting the type of the Response object.
• Response.url always returns '' (again, we'd have to patch undici to make this work)
• the test Fetch on 425 response should not be retried for non TLS early data. is failing, but Chrome also fails that test: https://source.chromium.org/chromium/chromium/src/+/main:third_party/blink/web_tests/external/wpt/fetch/api/basic/http-response-code.any-expected.txt;l=2;drc=f2d84e666d3463d55d7b6d78f2329941e389ae5a, so I don't think that's our fault. We fail it with a slightly different error message (0 connections created instead of 2 connections created).
• the 'integrity' feature is not implemented. In Chrome, this happens on the Blink side, not in the network service, so we'd have to reimplement it or borrow undici's implementation somehow.
• we don't correctly preserve http header case (we downcase all headers; the spec expects to keep the case of the first set header)

In addition, net.fetch doesn't support data: or blob: schemes.

I think none of these are sufficiently bad problems to prevent shipping, so I'm taking this out of draft mode.

[nornagon]

Ref electron/typescript-definitions#215

[deepak1556]

Seems like changes from #37099 are mixed in, a rebase would be good.

[release-clerk]

Release Notes Persisted

Added net.fetch().