Fix monaco editor localization

[msujew]

What it does

Closes #14995

After overriding the localize and localize2 function of monaco, some pieces still weren't translated correctly, since their keys didn't match up as expected anymore in the nls.metadata.json file which wasn't updated in a while. This PR also updates that file to ensure that everything is translated correctly.

Also deletes the old monaco-nls.json file which was no longer required (but I forgot to delete it).

How to test

1. Run the Configure Display Language command and select a non-English language
2. Ensure that all monaco menus/commands are correctly translated.

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[tsmaeder]

I've opened #15035 to track things that are not I18Ned even with this PR. Some of them seem to be simply oversights. I suggest we merge this one and address the remaining issue later.