added ledger as souec of funds for payouts

frontend/pshared/lib/models/payment/intent.dart

@@ -8,7 +8,9 @@ import 'package:pshared/models/payment/settlement_mode.dart';
 
 class PaymentIntent {
   final PaymentKind kind;
+  final String? sourceRef;
   final PaymentMethodData? source;
+  final String? destinationRef;
   final PaymentMethodData? destination;
   final Money? amount;
   final FxIntent? fx;
@@ -19,7 +21,9 @@ class PaymentIntent {
 
   const PaymentIntent({
     this.kind = PaymentKind.unspecified,
+    this.sourceRef,
     this.source,
+    this.destinationRef,
     this.destination,
     this.amount,
     this.fx,

frontend/pshared/lib/models/payment/source_type.dart

@@ -0,0 +1 @@
+enum PaymentSourceType { wallet, ledger }