small fixes for single payout and big chunck for multiple payouts

frontend/pweb/lib/models/multiple_payouts/csv_row.dart

@@ -0,0 +1,17 @@
+class CsvPayoutRow {
+  final String pan;
+  final String firstName;
+  final String lastName;
+  final int expMonth;
+  final int expYear;
+  final String amount;
+
+  const CsvPayoutRow({
+    required this.pan,
+    required this.firstName,
+    required this.lastName,
+    required this.expMonth,
+    required this.expYear,
+    required this.amount,
+  });
+}

frontend/pweb/lib/models/multiple_payouts/state.dart

@@ -0,0 +1 @@
+enum MultiplePayoutsState { idle, quoting, sending }