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.Common/MultiProcessingQueue.cs

@@ -23,7 +23,7 @@ namespace BTCPayServer
             internal Task ProcessTask;
             public async Task Process(CancellationToken cancellationToken)
             {
-                retry:
+retry:
                 while (Chan.Reader.TryRead(out var item))
                 {
                     await item(cancellationToken);
@@ -52,7 +52,7 @@ namespace BTCPayServer
         {
             lock (_Queues)
             {
-                retry:
+retry:
                 if (stopped)
                     return;
                 Cleanup();