Code formatting updates (#4502)

* Editorconfig: Add space_before_self_closing setting

This was a difference between the way dotnet-format and Rider format code. See https://www.jetbrains.com/help/rider/EditorConfig_Index.html

* Editorconfig: Keep 4 spaces indentation for Swagger JSON files

They are all formatted that way, let's keep it like that.

* Apply dotnet-format, mostly white-space related changes

BTCPayServer/Plugins/PointOfSale/Models/UpdatePointOfSaleViewModel.cs

@@ -98,7 +98,7 @@ namespace BTCPayServer.Plugins.PointOfSale.Models
         [Display(Name = "Custom CSS Code")]
         public string EmbeddedCSS { get; set; }
         public string Description { get; set; }
-        
+
         [Display(Name = "Require refund email on checkout")]
         public RequiresRefundEmail RequiresRefundEmail { get; set; } = RequiresRefundEmail.InheritFromStore;