Add custom inspect for node without depedency

[pedropedruzzi]

Adds back the custom inspection functions for node.js, first added by #281 then removed by #318 and [55ac17e]. This change avoids the default node's object inspection listing all fields recursively. This time there are no node imports or any run-time dependency. We simply expose the inspect functions as symbol-named attribute Symbol.for('nodejs.util.inspect.custom') as described in the docs.

Note: I've simplified the formats from the original addition to make it single line and simpler.

Testing done

• npm run build
• npm run format-check
• ./scripts/test
• Manual

const { DateTime, Duration, Interval } = require('./build/cjs-browser/luxon')
Duration.fromObject({ seconds: 10 })
Interval.fromDateTimes(DateTime.now().minus({ days: 1 }), DateTime.now())
DateTime.now()

// output:
Duration { values: {"seconds":10} }
Interval { start: 2023-10-09T16:20:51.017-03:00, end: 2023-10-10T16:20:51.019-03:00 }
DateTime { ts: 2023-10-10T16:20:59.623-03:00, zone: America/Sao_Paulo, locale: en-US }

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: pedropedruzzi / name: Pedro Pedruzzi (6fb10c2)

[icambron]

This looks good, thanks