Upconvert UFO v1 and v2 fontinfo and feature data

[madig]

This does a bit of work.

• UFO v1 stored feature code and the Postscript info attributes in lib.plist, which need to be sourced when upconverting: https://github.com/robotools/defcon/blob/a1e9d2852bb9d531ae5ec5b707fa0ab51aa202f1/Lib/defcon/objects/font.py#L1531-L1589
• UFO v1 had different names for the fontinfo attributes, some of which need conversion: https://github.com/fonttools/fonttools/blob/master/Lib/fontTools/ufoLib/__init__.py#L1934-L1962 (and possibly more code)
• UFO v2 and v3 have the same attribute names (v3 just has more), but v3 also updates the data types for some attributes (e.g. unitsPerEm are made positive)

ufoLib supports converting the versions up and down, but I think forcibly one-way upgrading the data to the latest supported version is the way to go for Norad.

The fontinfo error messages remain... rudimentary. I think they need to be revisited to return more useful error messages at a later point. I don't know how to get serde to include the field name in error messages if a field contains invalid data.

[cmyr]

looks good, one little nit but overall I'm happy to trust you ;)

[madig]

This works, but strikes me as somehow unrusty.

[cmyr]

Okay, one little suggestion but feel free to merge!