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

95% 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

@@ -137,7 +137,7 @@
     "show": "Показать",
     "size": "Размер",
     "upload": "Загрузить",
-    "uploadFiles": "Uploading {files} files...",
+    "uploadFiles": "Загружаю {files} файлы...",
     "uploadMessage": "Выберите вариант для загрузки.",
     "optionalPassword": "Необязательный пароль",
     "resolution": "Resolution",