Ability to copying authorization URL for Gmail (#375)

* Implemented copying auth URL for Gmail authentication.

* Update Button icon and add row spacing in Flyout grid

The icon used in the Button.Content has been updated to a new
design and is now wrapped inside a Viewbox with a width of 20
to ensure proper scaling. Additionally, the Grid inside the
Flyout now includes RowSpacing="12" to improve visual separation
between rows.

Wino.Core.Domain/Interfaces/IAuthenticatorTypes.cs

@@ -1,6 +1,9 @@
 namespace Wino.Core.Domain.Interfaces
 {
     public interface IOutlookAuthenticator : IAuthenticator { }
-    public interface IGmailAuthenticator : IAuthenticator { }
+    public interface IGmailAuthenticator : IAuthenticator
+    {
+        bool ProposeCopyAuthURL { get; set; }
+    }
     public interface IImapAuthenticator : IAuthenticator { }
 }