Add link for Japanese training-guides
Add link for Japanese training-guides

Add link to draft-i18n-manuals for previewing the Japanese
training-guides.

Change-Id: I16fa38433ff61410eec02553f050495f5c6e0748

openstack/openstack-manuals,openstack/openstack-manuals,potsmaster/openstack-manuals,kairoaraujo/openstack-manuals,potsmaster/openstack-manuals,gongysh2004/openstack-manual,saeki-masaki/openstack-manuals,Akasurde/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,Akasurde/openstack-manuals,saeki-masaki/openstack-manuals,kairoaraujo/openstack-manuals,gongysh2004/openstack-manual,openstack/openstack-manuals,openstack/openstack-manuals