Implement mail and calendar item synchronizer state (#815)

* Track pending sync operations per mail/calendar item

* Updated progressbar for in progress drafts

Wino.Core.Domain/Interfaces/IBaseSynchronizer.cs

@@ -1,4 +1,5 @@
-using System.Threading.Tasks;
+using System;
+using System.Threading.Tasks;
 using Wino.Core.Domain.Entities.Shared;
 using Wino.Core.Domain.Enums;
 using Wino.Core.Domain.Models.Accounts;
@@ -23,6 +24,18 @@ public interface IBaseSynchronizer
     /// <param name="request">Request to queue.</param>
     void QueueRequest(IRequestBase request);
 
+    /// <summary>
+    /// Returns whether there is an in-progress (queued or currently executing) operation for the given mail unique id.
+    /// </summary>
+    /// <param name="mailUniqueId">Mail unique id to check.</param>
+    bool HasPendingOperation(Guid mailUniqueId);
+
+    /// <summary>
+    /// Returns whether there is an in-progress (queued or currently executing) operation for the given calendar item id.
+    /// </summary>
+    /// <param name="calendarItemId">Calendar item id to check.</param>
+    bool HasPendingCalendarOperation(Guid calendarItemId);
+
     /// <summary>
     /// Synchronizes profile information with the server.
     /// Sender name and Profile picture are updated.