Move international sky culture choice out of Europe

[jidanni]

Perhaps move the international star names choice out of Europe sky culture, into a new International header.

[gzotti]

If you are against the culturally grown traditional constellation lines, just don't show them. If you want to limit yourself to IAU approved star names, use the "modern(IAU)" skyculture. Or create your own, the process is well described in the User Guide.

[github-actions]

We have a strong reason not to do it! Some reasons for it can be found in the FAQ:
https://github.com/Stellarium/stellarium/wiki/FAQ#Why_dont_you_implement