feat: Translate frontend/src/i18n/en.json in ru

98% of minimum 50% translated source file: 'frontend/src/i18n/en.json'
on 'ru'.

Sync of partially translated files: 
untranslated content is included with an empty translation 
or source language content depending on file format

frontend/src/i18n/ru.json

@@ -158,6 +158,7 @@
     "video": "Видео"
   },
   "settings": {
+    "aceEditorTheme": "Ace editor theme",
     "admin": "Админ",
     "administrator": "Администратор",
     "allowCommands": "Запуск команд",