Add expense editor

moneymgr_mobile/lib/services/storage/expenses.dart

@@ -13,6 +13,15 @@ part 'expenses.g.dart';
 
 typedef ExpensesList = List<Expense>;
 
+@freezed
+abstract class BaseExpenseInfo with _$BaseExpenseInfo {
+  const factory BaseExpenseInfo({
+    required String label,
+    required int cost,
+    required DateTime time,
+  }) = _BaseExpenseInfo;
+}
+
 @freezed
 abstract class Expense with _$Expense {
   const Expense._();