Japanese: implementation of duration attribute

[makorin0315]

The Japanese language model currently supports DateTime attribute, which mostly covers those expressions that can be either Time or Duration. However, there are certain expressions that can definitely be considered Duration, and detecting them would be helpful in both medical/clinical and standard text.

[makorin0315]

I found this issue while working on issue #221. Duraion attribute detection is simpler than Negation expansion, so I will resolve this issue first.