Figure out UI for translated policies and quotes

[Manishearth]

Translated policies are not the canonical source, and should have a banner saying that the official policy is the English one (linking to it).

Similarly, translated quotes are not real quotes. It's useful to have them be translated, but there should be some indication that they're not the original text.

Some kind of mini banner would be nice. I'm not precisely sure what the UI would look like here.

cc @vertexclique

[Manishearth]

If someone can figure out the UI and make a PR adding it in English to one policy page and one quote without dealing with translations at all, I can make it work so that it works everywhere and is translatable.