Internationalization/Localization

[AlbertoCasasOrtiz]

Currently, every string is hardcoded in the code directly in every repository. This makes difficult locate specific messages, titles, texts... in the code. We should internationalize the code, so we have every string in the same place and we can more easily find typos, add/modify error messages... etc.

Some parts of the code are already using react-i18next, so it will be easier. This will also allow translation to different languages in the future if requested.