Issue #1147 - js directory part 1

Issue #1147 (closed) will touch many files so instead of making one big MR, I think it is better to make many small ones. It will be much easier to review.

This first MR brings js/dom, js/i18n, and js/common up to typescript and the new standards. The are other changes in this code but none of them functional. Most non obvious changes are for clarity, type clarity, tech updates (specifically clipboard things here), and generally making functions shorter and more readable (this will also help with testability in the future).

There would be more MRs on this issue but since we only do one MR per issue I will retroactively change this ticket to be the update of these 3 files and make a new ticket to continue conversion