Printing mails. (#471)

* Implemented printing functionality.

* Implemented icon for printing.

* Remove debug code.

Wino.Core.Domain/Interfaces/IPrintService.cs

@@ -0,0 +1,10 @@
+using System.Threading.Tasks;
+using Wino.Core.Domain.Enums;
+
+namespace Wino.Core.Domain.Interfaces
+{
+    public interface IPrintService
+    {
+        Task<PrintingResult> PrintPdfFileAsync(string pdfFilePath, string printTitle);
+    }
+}