rubygem-fog-json (Fog::Json) provides extraction of the JSON parsing tools
shared between a number of providers in the 'fog' gem.
WWW: https://github.com/fog/fog-json
create USES=gem and update rubygem- ports to use it
Note that for now ports still have to have USE_RUBY=yes to use USES=gem
PR: 209041
Differential Revision: https://reviews.freebsd.org/D6070