Billing: Update EBICS exporter

Elwig/Helpers/Billing/Transaction.cs

@@ -1,32 +0,0 @@
-using Elwig.Models.Entities;
-using System;
-using System.Collections.Generic;
-using System.Linq;
-
-namespace Elwig.Helpers.Billing {
-    public class Transaction {
-
-        public readonly Member Member;
-        public readonly long AmountCent;
-        public readonly string Currency;
-        public readonly int Nr;
-
-        public Transaction(Member m, decimal amount, string currency, int nr) {
-            Member = m;
-            AmountCent = (long)Math.Round(amount * 100);
-            Currency = currency;
-            Nr = nr;
-        }
-
-        public static IEnumerable<Transaction> FromPaymentVariant(PaymentVar variant) {
-            var last = variant.Season.PaymentVariants.Where(v => v.TransferDate != null).OrderBy(v => v.TransferDate).LastOrDefault();
-            var dict = last?.MemberPayments.ToDictionary(m => m.MgNr, m => m.Amount) ?? new();
-            return variant.Credits
-                .OrderBy(c => c.MgNr)
-                .Select(c => new Transaction(c.Member, c.Amount, variant.Season.CurrencyCode, c.TgNr))
-                .ToList();
-        }
-
-        public static string FormatAmountCent(long cents) => $"{cents / 100}.{cents % 100:00}";
-    }
-}