support "public" company distinction

[petri]

In many countries, a "public" limited (liability) company has a distinction that its shares are publicly traded or -tradable. We don't have this distinction in cleanco currently.

[FBnil]

ISO20275 doesn't have that information either. We would need a list of "Limited", "Limitada", "合同会社", beperkte, etc... in all languages to detect it from the long written out versions. I'm not a legal person, so I do not know if, say, church communities are also with implicit "limited").