Enhance React i18n module

[fabienpuissant]

To follow the idea of what have been done in the VueI18nModule, the React one module needs the be adapted.

• Use a setup file to mock react i18n for all tests
• Separate translations to be scoped to each bounded context in separate translation files

[fabienpuissant]

@DamnClin @Gnuk

We need to decide what we want for front translation design (#11111)

Vue Ts configuration with multiple bounded context files

React one json file with all translations

Because rn, React and Vue are not aligned and I would like to make them work the same way 😃

[Gnuk]

I think you can split translations by context. If it's easier to be consistent with JSON, we can start with it and maybe later (in the future) we will be able to use typescript type system to check translation keys.