As per title, I believe calling i18n is bad because it's a singleton.
This singleton is being set back and force by users in
i18n.middleware.ts
Strategy:
we need to load the translations dynamically! Should be straight
forward:
- singleton (i18nService) containing all translationMessages
- singleton also containing a map of i18n instances loaded for each
locale => I've checked it's not heavy on RAM at all
- some methods to get the translation for a messageId x locale or the
whole i18n instance
==> use it everywhere, this PR only takes care of data model translation
