refs https://github.com/TryGhost/Ghost/issues/13380
- Now that i18n.t has been removed everywhere, we can cleanup the final usages
- Still TODO: merge the i18n logic into themeI18n, and get rid of shared/i18n entirely
- We have a bunch of important server-related e2e tests
- Make these clear in their own folder
- "server" is everything that isn't the api or the frontend - kind of a catch-all concept