[Refactor] Move SQL classes in their own assembly

BTCPayServer/Data/AddressInvoiceDataExtensions.cs

@@ -0,0 +1,39 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using BTCPayServer.Payments;
+
+namespace BTCPayServer.Data
+{
+    public static class AddressInvoiceDataExtensions
+    {
+#pragma warning disable CS0618
+        public static string GetAddress(this AddressInvoiceData addressInvoiceData)
+        {
+            if (addressInvoiceData.Address == null)
+                return null;
+            var index = addressInvoiceData.Address.LastIndexOf("#", StringComparison.InvariantCulture);
+            if (index == -1)
+                return addressInvoiceData.Address;
+            return addressInvoiceData.Address.Substring(0, index);
+        }
+        public static AddressInvoiceData Set(this AddressInvoiceData addressInvoiceData, string address, PaymentMethodId paymentMethodId)
+        {
+            addressInvoiceData.Address = address + "#" + paymentMethodId.ToString();
+            return addressInvoiceData;
+        }
+        public static PaymentMethodId GetpaymentMethodId(this AddressInvoiceData addressInvoiceData)
+        {
+            if (addressInvoiceData.Address == null)
+                return null;
+            var index = addressInvoiceData.Address.LastIndexOf("#", StringComparison.InvariantCulture);
+            // Legacy AddressInvoiceData does not have the paymentMethodId attached to the Address
+            if (index == -1)
+                return PaymentMethodId.Parse("BTC");
+            /////////////////////////
+            return PaymentMethodId.Parse(addressInvoiceData.Address.Substring(index + 1));
+        }
+#pragma warning restore CS0618
+    }
+}