Add sample Japanese content

* Rosetta menu
* Posts (4.0 and 4.0.1 JA blog posts)
* Pages ( /txt-welcome, /faq and /contact)
* Showcase Examples (Per JA showcase)
Rosetta provisioning

* Add JA & ES Rosetta translations
* Add JA multibyte patch plugin
https://wordpress.org/plugins/wp-multibyte-patch/