Epoch date will not be set through the API
Create retro invoices by lease
Fixed overlap issue in LocalDateInterval
EST-319: Possibility to have invoicing frequency that are fixed and use the start and end date of the term
Refactoring LeaseCalculation; enhancing CreateRetroInvoices to accept leases; renaming InvoiceItemsForLease methods
The turnover rent calculation is again using the original invoicing frequency of the rent items

Regression is covered by retro invoices test.
Cleanup and adding tests