Provide ability to specify cancellation reason in accounts/:id/cancel request

Overview: When an account is cancelled through /accounts/:id/cancel API, the account always have Payment status = Cancelled as error. However, it is not a proper status for some cases and may confuse end users, for example when an account for lost item fee is cancelled because item is found and returned we should cancel the account as Cancelled item returned (it was not an error).

1. Scenario:

• Given account cancellation request;
• When cancellationReason property set in cancellation request;
• Then:
  • Account.paymentStatus.name = cancellationReason
  • AccountAction.typeAction = cancellationReason

2. Scenario:

• Given account cancellation request;
• When cancellationReason property is NOT set in cancellation request;
• Then:
  • Account.paymentStatus.name = "Cancelled as error"
  • AccountAction.typeAction = "Cancelled as error"

CC: OleksandrVidinieiev. hollyolepm, marcjohnson, cboerema.