Adds util.parseArgs helper for higher level command-line argument parsing.

Background

There has been an ongoing effort in pkgjs/parseargs to define a command-line argument parsing API for Node.js core.

The effort has taken several years to get to this point, with many amazing contributors across a variety of companies and projects: IBM, Microsoft, Google, Shopify, npm, nvm, commander, yargs, just to name a few.

Where parseArgs is at

@shadowspawn, who's been most recently pushing a lot of the work on parseArgs forward, indicates in pkgjs/parseargs/issues/87 that "we're close to having a decent MVP."

I agree, and thought it would be worth having a candidate PR open on Node.js to get additional feedback.

This is a controversial topic, be kind

There's a lot of nuance and opinion, as to what constitutes a "decent MVP" for a command-line argument parser. Please be respectful of opinions you might not agree with 😊

Before leaving feedback on this thread, I suggest reading past issues on parseArgs. Perhaps there's already been a discussion that touches on your feedback (or there's an ongoing discussion).

Similarly, if themes of discussion jump out in this PR, let's move them to an issue in parseArgs (this should help keep this PR less confusing).

ToDo

• PR: should flags be removed consolidating on values.~ landed
• PR: strict mode handling. landed
• Issue: should poisitional parsing be opt-in.
• finish audit of prototype pollution.

CC: @ljharb, @bakkot, @iansu, @darcyclarke, @ruyadorno, @shadowspawn, @nodejs/tooling, @Trott (who I believe asked after this), @aaronccasanova.