Update simplified Chinese translation and create Chinese install-readme-zh

Updated the Simplified Chinese translation for v 1.2 aka the English version(pushed by [commit 903686](https://github.com/philippK-de/Collabtive/commit/903686508ca42fd34e5d7c08d616ee79aa0c1276)).

Details:
file ./languge/zh/lng.conf
1. Removed all deprecated lines
2. Implemented some untranslated lines
3. Translated the new lines that have been added since the last version of the Chinese translation.

file ./install-readme-zh.txt
1. Translated into Chinese from the install-readme-en.txt