Menu editor: 67 new strings, translations to review

The next release adds a menu editor (options page > Menus) and 67 new strings in _locales/en/messages.json (keys starting with menus, optionMenus, plus menuSubmenu, menuSeparator and editorArchiveToc).

To avoid shipping English fallbacks, I committed draft translations for all locales (2e228acf here, bd2a09f in SingleFile-MV3). They were produced with machine assistance and only checked for terminology consistency with the existing files, so they are drafts, not a substitute for your work. If you maintain one of these locales, please feel free to correct them or to replace them entirely with your own wording, the way you usually do. No rush, this can land in a later release.

@solokot (ru) @xesarni (pl) @NickWick13 (sv) @frostblazergit (zh_CN) @notlin4 (zh_TW)