Support adding text data for other languages

[mia-pi-git]

This is only the server-side portion of translating battle messages/data. Requires client work that I'll PR once we sort out some structure details here (@KrisXV indicated they weren't a huge fan of the current directory setup).

As it is, this PR simply sorts divides data/text into subdirectories, so that new directories can be added for new language data (and it adds relevant support in Dex/etc).