Category metadata

[amake]

I have a use case where I would like to offer users the ability to select a font from this package, but there are just so many that it's overwhelming.

In particular, I would like to be able to narrow the list down to only monospace fonts, but there's currently no clean way to do so (without e.g. manually collecting font names from https://fonts.google.com/?category=Monospace).

It would be nice if we could programmatically obtain the category (Serif, Sans Serif, Display, Handwriting, Monospace) of each font. For instance asMap() could have a counterpart byCategory() or similar.

[guidezpl]

I like this idea!