Update price display (#4736)

* Update price display

As proposed by @dstrukt in #4364.

* Update format

* Unify price display across the app

* Add DisplayFormatter

* Replace DisplayFormatCurrency method

* Use symbol currency format for invoice

* Unify currency formats on backend pages

* Revert recent changes

* Do not show exchange rate and fiat order amount for crypto denominations

* Fix test and add test cases

BTCPayServer/Models/InvoicingModels/InvoicesModel.cs

@@ -28,7 +28,8 @@ namespace BTCPayServer.Models.InvoicingModels
         public bool CanMarkStatus => CanMarkSettled || CanMarkInvalid;
         public bool ShowCheckout { get; set; }
         public string ExceptionStatus { get; set; }
-        public string AmountCurrency { get; set; }
+        public decimal Amount { get; set; }
+        public string Currency { get; set; }
 
         public InvoiceDetailsModel Details { get; set; }
         public bool HasRefund { get; set; }

BTCPayServer/Models/ViewPullPaymentModel.cs

@@ -82,7 +82,6 @@ namespace BTCPayServer.Models
         public decimal ClaimedAmount { get; set; }
         public decimal MinimumClaim { get; set; }
         public string Destination { get; set; }
-        public string AmountDueFormatted { get; set; }
         public decimal Amount { get; set; }
         public string Id { get; set; }
         public string Currency { get; set; }
@@ -97,8 +96,6 @@ namespace BTCPayServer.Models
         public DateTimeOffset StartDate { get; set; }
         public DateTime LastRefreshed { get; set; }
         public CurrencyData CurrencyData { get; set; }
-        public string AmountCollectedFormatted { get; set; }
-        public string AmountFormatted { get; set; }
         public bool Archived { get; set; }
         public bool AutoApprove { get; set; }