Deposits are now invoiced separately

We've changed how deposits work in getSoapy.

If you use split invoices with the first instalment taken as a deposit, scheduling a job now raises a deposit invoice for just the deposit, and the rest is invoiced when the job is done. The final invoice also shows the deposit being taken off.

We've made this change because it's more in line with standard accounting practice, and because businesses and customers told us they'd expect deposits to work this way.

We've also added a few related updates:

• a new Deposits are due setting in Payment options
• a Deposit unpaid label on jobs in Work view and the calendars
• a new Deposit Requested notification
• deposit wording for overdue reminders and invoices

For everyone, payments and customer credit now go to whatever is due first, instead of the oldest invoice. That should mean fewer cases where someone has paid, but still gets chased for the wrong thing.