i18n: init using react-i18next

[sorpaas]

This adds an i18n framework using react-i18next. Using this by:

1. import { translate } from 'react-i18next';
2. Wrap the component using translate("category")(...) and use t("name", { ...options }) for texts to be translated.
3. Add the required translation name in locales/lang/category.json.

[sorpaas]

@dulanov How will this PR be dealt with? Seems right now we've got conflicts. Should I push this at a later time or it is possible to start translation now?

[ghost]

Always resolve conflicts firstly, @elaineo answer please, is it ok to merge it now?

[elaineo]

Ah! Is this a followup to the discussion on slack about adding language support? Everything looks fine to me, but I assume this will be a work in progress, right?

(okay to merge, but we should also open an Issue about adding language support to keep track of progress)

[sorpaas]

I've got the framework in. It's working. 😂 So in my opinion it's okay to merge. After that we can gradually replace hard-coded texts with t(...) and add translations.

I'll resolve the conflicts now.

[CLAassistant]

All committers have signed the CLA.