[gentoo-doc] Japanese translated docs have been maintained

[shindo]

Hi all, 

I'm (actual lead) translator of Japanese Gentoo docs.

This 6 month, Japanese translation team has been activated, 
so then translations of Handbook Part1(x86), Alternative Installation Guide,
Security handbook and ALSA Configuration Guide are completely updated.
And Handbook Part2 is almost updated, all part2 docs will be
completed soon.
Of course, our team will translate other docs step by step.

Can Japanese come back to available language list on
www.gentoo.org?
(Translations is maintained already!)

Shindo