refs https://github.com/TryGhost/Ghost/issues/15502
- this adds the scaffolding for enabling i18n translations within Ghost
core
- also adds `yarn translate:ghost` as an option to the `i18n` package
- the locale is currently hardcoded to `en` so we don't utilize the
translations until we're ready
refs https://github.com/TryGhost/Ghost/issues/15502
- the amazing `i18next-parser` dependency will extract our translated
strings from Portal and dump them into locale files, so we never have
to add them manually
refs https://github.com/TryGhost/Ghost/issues/15502
- this is an early implementation of an i18n provider by
exporting an instance of `i18next`
- there's a lot more to be done here but baby steps :)