Merge Simplified Chinese translation for the website.

Obtained from: The FreeBSD Simplified Chinese Project
Thanks goes to: Gavin MU <gavin.mu at gmail dot com> [1],

		Fukang CHEN <loader at freebsdmall dot com> [2],
		intron <intron at intron dot ac> [3]

[1] The original translation with me.
[2] New layout and structural improvements.
[3] Additional and continued contributions.