i18n: new translations for Chinese Simplified and Arabic (#578)

Co-authored-by: Saber <sabersalv@gmail.com>
Co-authored-by: yngams <unknown@unknown>

client/src/javascript/i18n/strings/ar.json

@@ -239,6 +239,7 @@
   "torrents.details.files.loading": "تحميل تفاصيل الملف...",
   "torrents.details.general.comment": "تعليق",
   "torrents.details.general.connected": "{connected} متصل بـ {total}",
+  "torrents.details.general.date.active.now": "الآن",
   "torrents.details.general.date.added": "أضيف",
   "torrents.details.general.date.finished": "منتهى",
   "torrents.details.general.downloaded": "تم التحميل",

client/src/javascript/i18n/strings/zh-Hans.json

@@ -346,6 +346,7 @@
   "torrents.properties.comment": "备注",
   "torrents.properties.date.added": "添加时间",
   "torrents.properties.date.created": "创建时间",
+  "torrents.properties.date.finished": "完成时间",
   "torrents.properties.directory": "位置",
   "torrents.properties.download.speed": "下载速度",
   "torrents.properties.download.total": "已下载",