Mostly what @goto-bus-stop did in 4f51deaaf7 (diff-989af75a364b65c408abe1fc3e7ac0f4R34)
> This patch allows locale keys passed to the main Uppy instance to override default keys in plugins. It's just one idea to kick things off, I'm not attached to this particular implementation.
>
> If we do this we need to make sure that all keys have unique names and that things specific to eg. a single service are "namespaced" (`transloaditEncoding` instead of `encoding`).
>
> The benefit to this is that there is a central point of configuration for languages, so there could be language packs with strings for eg Czech at `@uppy/lang-cz` (or `@uppy/langs/cz`) that would be very easy to use.
Available as `@uppy/utils/lib/Translator`.
The Translator tests were using `Core()` instead of `Translator()`, so I
changed it to using `Translator` instances directly. The functionality
being tested did not change.
Steps taken:
```bash
git mv src/core/Translator.* packages/@uppy/utils/src
sed -i 's/[./]*\/core\/Translator/@uppy\/utils\/lib\/Translator/' src/**/*.js
vim packages/@uppy/utils/src/Translator.test.js # Fix tests
```
