Ground work for Wino Calendar. (#475)

Wino Calendar abstractions.

Wino.Messages/Client/Navigation/NavigateManageAccountsRequested.cs

@@ -0,0 +1,7 @@
+namespace Wino.Messaging.Client.Navigation
+{
+    /// <summary>
+    /// Navigates to manage accounts page.
+    /// </summary>
+    public record NavigateManageAccountsRequested;
+}

Wino.Messages/Client/Navigation/NavigateSettingsRequested.cs

@@ -1,7 +0,0 @@
-namespace Wino.Messaging.Client.Navigation
-{
-    /// <summary>
-    /// Navigates to settings page.
-    /// </summary>
-    public record NavigateSettingsRequested;
-}