Add separate recovery seed backup view

fix

BTCPayServer/Models/StoreViewModels/RecoverySeedBackupViewModel.cs

@@ -0,0 +1,21 @@
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using Microsoft.AspNetCore.Http;
+using NBitcoin;
+
+namespace BTCPayServer.Models.StoreViewModels
+{
+    public class RecoverySeedBackupViewModel
+    {
+        public string CryptoCode { get; set; }
+        public string Mnemonic { get; set; }
+        public string Passphrase { get; set; }
+        public bool IsStored { get; set; }
+        public string ReturnUrl { get; set; }
+
+        public string[] Words
+        {
+            get => Mnemonic.Split(" ");
+        }
+    }
+}