Add the Japanese introduction page for LXD

Signed-off-by: KATOH Yasufumi <karma@jazz.email.ne.jp>
Merge pull request #18 from tenforward/japanese

Add the Japanese introduction page for LXD
Change link to each introduction page on Japanese front page

Signed-off-by: KATOH Yasufumi <karma@jazz.email.ne.jp>
Merge pull request #19 from tenforward/japanese

Change link to each introduction page on Japanese front page