i18n module

Internationalization module using format.js (https://formatjs.io/)

Could be use to centralize all locale-related data. Contains two locales (fr, en) for now A function is available to format a given string when used in a node context (see unit test) When used in a react context, the react-intl library (integration of format.js core library for react component) would only need the locale files

As an example of internationalization in a node context, I used this module for the parser (cf other merge request) I will try to use it in a react context soon to translate interface text (for now we just hard coded our french version).

What do you think ? Would you be interested in having i18n in the rest of editoria ?