PRSD-353: Registration Number Service

[isobel-softwire]

Overarching Changes

• Creates base ModifiableAuditableEntity and makes AuditableEntity its descendant.
• Creates base ServiceTest
• Creates RegisteredEntity interface for entities with registration numbers (this allows for generic RegistrationNumberService methods)

Features

• Adds RegistrationNumber and a Landlord skeleton to the database.
• Creates RegistrationNumberService that can:
  • Create registration numbers
  • Convert between integer and formatted registration numbers
  • Retrieve an entity based on its registration number
• Displays a formatted registration number on the webapp's landing page for PoC.

Tests

• Tests for RegistrationNumberService methods

Notes

• Decided against displaying a registration number based on seed data as the features required for this are outside this ticket's scope.
• TODOs left in RegistrationNumberService.retrieveEntity as entities with registration numbers (apart from landlord) are yet to be implemented.

[Travis-Softwire]

Overall looking good I think. I've left a few comments, but would appreciate @rowanhill's view as he designed the registration numbers :)

[rowanhill]

Thanks for all the tweaks - this looks good to me now!