CodeIgniter4-translations

@thanhtunguet
I don't like this idea, because

1. we end up with two copies of the same thing, in different repositories; they would need synch'ing
2. anyone contributing a translation would only do so if they had already forked the main repo, where ths system/Language/en folder is found; that would be a new contributor's starting point.

Better would be a way to integrate them, perhaps using a github submodule (?)
The original and authoritative copy needs to live inside the main repo, just like the user guide source, so that PRs to the main repo can be complete, i.e. including any language file entries needed, as well as user guide pages/changes and unit testing.

A tool that would be useful for the translations repo would be a script to look for missing translations, e.g. when the main repo was updated, and which could be run on its own (by a translator) or as part of travis-ci for new PRs (which would admittedly not help with existing translation which were now missing one or more entries).

Long-term, we need to figure out something, I agree.