docs/zh_CN: Add userspace-api/seccomp_filter Chinese translation

Translate the following documents into Chinese:

- userspace-api/seccomp_filter.rst

Also adjust index order according to the original index file.

Signed-off-by: Rui Li <me@lirui.org>
Reviewed-by: Wu XiangCheng <bobwxc@email.cn>
Reviewed-by: Yanteng Si <siyanteng@loongson.cn>
Link: https://lore.kernel.org/r/20221108112921.312071-1-me@lirui.org


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