[Repository] Create account repository interface and doctrine account repository
[Account] Declare repository class
[Controller] Switch from ObjectRepository to AccountRepository
[Model] Create Bill model
[Create Bills For Account] Create command and handler to create bills and attach to an account
[Tests] Test bill creation subscriber and command handler
[Account] Add default closure date of opening date plus 1 year
[Account] Remove null check as there is a default to be set
[Account] Add methods to get more information
[Tests] Update account testing suite