docs/zh_CN: add virt acrn introduction translation

Translate Documentation/virt/acrn/introduction.rst into Chinese.

Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Alex Shi <alexs@kernel.org>
Link: https://lore.kernel.org/r/667a6eb64820d2234d12a0c5dd5b642af16c0d99.1628212777.git.siyanteng@loongson.cn


Signed-off-by: Jonathan Corbet <corbet@lwn.net>