feat(lib/lib.less): add rgbify/hslify config options

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Less minimal playground demo (link fixed)

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Hslify demo

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Option naming and behavior still up to changing, just a PoC that I'm excited about :)

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Notably this is (or at least should be 🤞) backwards entirely compatible.

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Note: can technically be simplified with this syntax but it is less readable when formatted.

Suggested change

	@with-spaces: red(@color) green(@color) blue(@color);
	@with-commas: red(@color), green(@color), blue(@color);
	@result: if(@spaces = true, @with-spaces, @with-commas);
	@result: if(@spaces = true; red(@color) green(@color) blue(@color); red(@color), green(@color), blue(@color));