Add support for multiple languages

[patcon]

I've always had a hard time getting English-speaking groups to use Hackfolder, and it seems to mostly be a reflection of the non-English language communicating "this is not for you".

I'd like to discuss how multilingual support (i18n) might be possible :)

Here are some thoughts -- 🔍 facts, feelings ❤️ and 💡 ideas -- related to this issue:

1. 🔍 hackfoldr is totally client-side
2. 🔍 Multilingual support on same page can hurt SEO.
3. 🔍 The recommended tactic for best SEO is to use different routes for each language: example.com/en/:slug
4. 🔍 No pages of hackholdr.org or subdomains are indexed in Google right now.
5. ❤️ I feel that perhaps we could ignore SEO advice because we already aren't very SEO-compatible.
6. 🔍 i18next is a popular multilingual JS framework.
7. ❤️ I feel uncertain whether i18next is right for us
8. 🔍 i18next has a browser language detector plugin for apps like hackfoldr.
9. 💡 We could use i18next without language routes, since we're not getting hit by SEO and this will be minimal change from current hackfoldr.
10. 🔍 i18next can easily pull translations from a url stored at one of the app's endpoints.
11. 🔍 This is a codepen example of the simple behavior described above.
12. 💡 The MVP could use javascript's navigator property to auto-detect language.
13. 💡 We could later add a langauge selector and use the detector's cookie/localStorage features.

[patcon]

Open Questions

1. Am I posting this in the right place?
2. Where do I submit the pull request?
3. Do you think this is a good idea?
4. Who makes merge decisions? Would it be a welcome addition in their opinion?
5. Is the described approach a decent one? Should more research be done?

[patcon]

Working on translations here: https://gist.github.com/patcon/1f68d3efd30360048bce81b3a7655c5b