Further expand data model

[bglamadrid]

Add entity, POJO, repository, crud service and data controller for the following entities:

• [x] Address (one-to-many for sales, twice; shipping + billing)
• [x] BillingCompany (one-to-many for sales)
• [x] Shipper (one-to-many for sales)
• [x] PaymentType (one-to-many for sales)

Besides, apply these changes.

• [x] SellType renamed to BillingType