Goaccess: Add Chinese localization

It would be great if we could add Chinese. Would you be able to translate the relevant labels? All the i18n plumbing has been done (gettext) and it'll be out in the next release. Here are the labels that need to be translated.

These are the steps:

1. Add zh_CN to the po/LINGUAS
2. Create a po/zh_CN.po file and add all your translations in there. See fr.po
3. run intltool-update zh_CN inside the po folder
4. run intltool-update --pot
5. Please submit a PR so I can merge it here.

If your locale is set to zh_CN, goaccess' output will automatically display its content in Chinese.

Let me know if you have any questions. Thanks!

No problem! I would love to translate the labels. I will do a PR after it's done.

Thanks very much! This has been added. Here's a screenshot:

Let me know if that looks/reads well.