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/Controllers/UIAppsController.cs

@@ -35,7 +35,7 @@ namespace BTCPayServer.Controllers
         private readonly AppService _appService;
 
         public string CreatedAppId { get; set; }
-        
+
         public class AppUpdated
         {
             public string AppId { get; set; }
@@ -46,14 +46,14 @@ namespace BTCPayServer.Controllers
                 return string.Empty;
             }
         }
-        
+
         [HttpGet("/apps/{appId}")]
         public async Task<IActionResult> RedirectToApp(string appId)
         {
             var app = await _appService.GetApp(appId, null);
             if (app is null)
                 return NotFound();
-            
+
             return app.AppType switch
             {
                 nameof(AppType.Crowdfund) => RedirectToAction(nameof(UICrowdfundController.ViewCrowdfund), "UICrowdfund", new { appId }),