Create cn.js (#1768)

* Create cn.js
Add chinese translation
* added additional files for chinese language
* Update lnbits/templates/base.html

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Co-authored-by: hodlbaby <52352588+hodlbaby@users.noreply.github.com>
Co-authored-by: dni ⚡ <office@dnilabs.com>

lnbits/templates/base.html

@@ -303,6 +303,7 @@
         {value: 'de', label: 'Deutsch', display: 'DE'},
         {value: 'es', label: 'Español', display: 'ES'},
         {value: 'jp', label: '日本語', display: 'JP'},
+        {value: 'cn', label: '中文', display: 'CN'},
         {value: 'fr', label: 'Français', display: 'FR'},
         {value: 'it', label: 'Italiano', display: 'IT'},
         {value: 'pi', label: 'Pirate', display: 'PI'},