Documentation: Add HOWTO Japanese translation into rst based build system

This commit adds Japanese translation of HOWTO document into rst based
documentation build system with updates.

Signed-off-by: Tsugikazu Shibata <tshibata@ab.jp.nec.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>