Implement CLI Argument Parser

[unfetchable]

Derived from frkcli, cc @itsfrank

Closes #83

This provides a lightweight, flexible CLI argument parser for Luau. It allows handling positional arguments, options, and flags, making it easier to build scripts that are dependent on the CLI.

[itsfrank]

Very cool that my library was helpful!

I don't have time to look too deeply into the code, but my initial thought is that we probably want a different name than argparse

I am certain you are aware, but argparse is the standard CLI parser for python and is massively popular. It has been re-implemented in a variety of languages, some of which re-use the name.

I think that we should only opt to use that name if we are explicitly re-implementing argparse's interface as faithfully as reasonably possible in Luau.

After a quick glance it does not seem that this implementation is trying to match argparse's interface, thus I would opt for a different name to avoid confusion.

[aatxe]

Yeah, that's a valid point, Frank! Maybe something like cliargs or something. I'm not really trying to name things in very "novel" ways for batteries since the point is kinda to just be boring utilities that people will almost certainly end up writing better versions of in the future.

[aatxe]

Suggested change

	export type ParserType = setmetatable<ParseData, ParseInterface>
	export type Parser = setmetatable<ParseData, ParseInterface>

The one that is actually exposed should have an "ordinary" type name, don't need to overcomplicate it.

[deviaze]

I'd just name it cli for simplicity.

[aatxe]

I'll do the file rename and type rename myself after it's merged in, I guess.