Implement localization

[jsha]

Right now we only support English. We'd like to support translated versions of some pages. Probably the best way to do this is to provide alternate URLs under each language code, e.g.:

https://letsencrypt.org/docs/rate-limits/
https://letsencrypt.org/kr/docs/rate-limits/

With a drop-down offering various languages. As an alternate, while we are getting our first few translations in, we may want to skip the drop-down in favor of having a language select at the top of specific pages that have translations. E.g. "This page is available in: English | Korean | Japanese"

[ventolinmx]

Hi
How can i help with translation to spanish?

[bdaehlie]

We have localization support now.

[ventolinmx]

Cool, where?