Separation of messages. Introducing Wino.Messages library.

Wino.Messages/Shell/CreateNewMailWithMultipleAccountsRequested.cs

@@ -0,0 +1,16 @@
+using System.Collections.Generic;
+using Wino.Core.Domain.Entities;
+
+namespace Wino.Messages.Shell
+{
+    /// <summary>
+    /// When 
+    /// - There is no selection of any folder for any account
+    /// - Multiple accounts exists
+    /// - User clicked 'Create New Mail'
+    /// 
+    /// flyout must be presented to pick correct account.
+    /// This message will be picked up by UWP Shell.
+    /// </summary>
+    public record CreateNewMailWithMultipleAccountsRequested(IEnumerable<MailAccount> AllAccounts);
+}