Add Chinese Translations (#56)

Add Chinese translations and fixed an translation error.

src/_locales/zh_CN/messages.json

@@ -584,7 +584,7 @@
     "description": "Edited site"
   },
   "deleteSiteConfirmation": {
-    "message": "您确定要删除次网站吗？",
+    "message": "您确定要删除此网站吗？",
     "description": "Are you sure you want to delete this site?"
   },
   "deletedSite": {
@@ -602,5 +602,21 @@
   "lost2FAApp": {
     "message": "认证应用已丢失？",
     "description": "Lost authenticator app?"
+  },
+  "credits": {
+    "message": "贡献人员",
+    "description": "Credits (giving thanks to people that helped, like at the end of a movie)"
+  },
+  "thankYou": {
+    "message": "非常感谢",
+    "description": "Thank You"
+  },
+  "translations": {
+    "message": "译者",
+    "description": "Translations"
+  },
+  "searchFolder": {
+    "message": "搜索文件夹",
+    "description": "Search folder"
   }
 }