Font selection

Does the scope of Oxidize include font selection (from family, style attributes, script, locale, and eventually `char` or [Unicode Range](https://learn.microsoft.com/en-us/typography/opentype/spec/os2#ulunicoderange))?

Existing Rust crates:

- `fontdb` supports loading a system database and querying by family and style attributes, but misses things like selecting the default UI font, using font aliases (aka how `fontconfig` provides alternatives to common copyrighted fonts like Arial), finding fallback fonts by script / locale
- `fontique` is in a similar position, albeit with some support for finding fallback fonts (though locale and script won't affect the preferred font match for common `char`s like ` ` or `.`)

Related: https://github.com/linebender/parley/issues/379