As per request #18391, we should only use one gettext library as mixing two separate libs is very brittle and makes us jump through hoops to keep it working.

Therefore, we should kill vue-gettext usage in the Angular artifact modal. We chose this one because all apps depending on the artifact modal rely on angular-gettext, and are therefore configured to make it work. We should stick to this lib at least until the artifact modal is built as a separate lib. Only then can we consider changing, but it is worth mentioning that both of these libs can be used outside of their framework (in vanilla JS / TS context for example).

As a nice side-effect, this will kill the only last remnant of Gulp usage in Tuleap (which means fewer npm packages to deal with 😊).
As another nice side-effect, using make generate-po will also finally extract translations in the artifact modal.