Gmail - Archive/Unarchive (#582)

* Disable timer back sync for debug builds.

* Archive / unarchive feature for Gmail.

* Archive folder name override for Gmail.

* Possible crash fix when the next item is being selected after a mail is removed.

* Restore proper account selection after pin/unpin of folder.

* Making sure that incorrect arcive folder id is not saved in Gmailsynchronizer due to migration.

Wino.Mail.ViewModels/MailListPageViewModel.cs

@@ -711,7 +711,10 @@ public partial class MailListPageViewModel : MailBaseViewModel,
 
             if (isDeletedMailSelected && PreferencesService.AutoSelectNextItem)
             {
-                nextItem = MailCollection.GetNextItem(removedMail);
+                await ExecuteUIThread(() =>
+                {
+                    nextItem = MailCollection.GetNextItem(removedMail);
+                });
             }
 
             // Remove the deleted item from the list.