Extricate char-def library to ... somewhere

[alerque]

In the same spirit as #669 and #670, the char-def blob in lua-libraries can probably go. In it's current format it generates lint errors because of it's global access method but I'm ignoring that for the moment in #168

This data is probably in the Unicode CLDR data set that I'm already abstracting into a Lua Rock of its own and bringing in as part of #665 (will land with PR #675).

[alerque]

So it seems this data is not part of CLDR at all, but actually part of another Unicode data-set called UCD. I'm not sure yet whether than belongs in cldr-lua or on its own somewhere. Just linking that discovery here for whenever I try to deal with this (or when anybody else takes it up).

[simoncozens]

Char-def was stolen from https://source.contextgarden.net/tex/context/base/mkiv/char-def.lua
Reformatting should be done with a script, and should include re-writing it to be a module which returns its data.