feat(i18n): add missing localizations

[megamegax]

I've noticed, that there are a lot of hardcoded strings in the project. I've started to extract them into localized strings as that is something anyone can do and benefits everyone at the end :)

This is the first batch, I plan to do it in small chunks a few files a time.

May I ask wether filling the existing localization jsons with the new strings is necessary or I can just skip that step in the future?

Also, do you approve the initiation or should I just leave it?