Please mark gnucash zh_CN as external

[Christian Stimming]

Dear TP maintainer,

(the subject says it all)

In the gnucash domain, please mark the zh_CN language as external. The 
external contributor has already contacted the zh_CN team and makes sure to 
merge the work.

Also, I would suggest to remove the two languages az and rw from gnucash, as 
they are close to empty and thus rather useless.

Thank you very much!

Regards,

Christian Stimming