Improve support for division names in multiple languages

[jdmgoogle]

There have been a few PRs/issues where the question of "in which language should the name of the district be represented?" As far as I know we don't have a great solution for this right now.

I would propose that we update the header format to allow headers of the form name:[language code]; e.g., name:en-US, name:de, name:es-419, etc. We'd have to figure out what to do with existing name columns (default to assume English?), but this could allow us to resolve the "in which language?" issue going forward.

Thoughts?

[jpmckinney]

Noting that for Canada, name_fr is used (ad-hoc). Colon makes more sense as a separator.