Prepare align by adding `label` to table and crawl entities based on `ontology class`.

I added labels in order to align graphs easier.
`tvtropes` uses name as plain text in English, so I decided to use English label.

In addition, I started to crawl entities which are belong to `ontology class`, such as `Artist`, `Film` ... and so on.
but the JSON list `item` has variable properties, if I use default default constructor, I need to make several `fetch_classes` for each `Entity`, `Artist`, .. etc.