Moving CrowdfundSettings in its own file

BTCPayServer/Models/AppViewModels/UpdateCrowdfundViewModel.cs

@@ -2,6 +2,7 @@
 using System.Collections;
 using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;
+using BTCPayServer.Services.Apps;
 
 namespace BTCPayServer.Models.AppViewModels
 {
@@ -81,13 +82,4 @@ namespace BTCPayServer.Models.AppViewModels
         [Display(Name = "Display contribution ranking")]
         public bool DisplayPerksRanking { get; set; }
     }
-
-    public enum CrowdfundResetEvery
-    {
-        Never,
-        Hour,
-        Day,
-        Month,
-        Year
-    }
 }