Added activation logic to automatically create an item for accounting for bill rounding
Added rounding function to round bill totals based on Cashier Module options
Added utility function for adding a rounding line item to a bill
Added tests
Modified RoundingUtil to use addPrice()
Refactored CashierOptions => added ICashierOptionsService and a global properties implementation
Added CashierOptions service tests and test data
Added global properties & constants for rounding item & department
Merge branch 'feature/roundingitem' into develop