introduce a TransientNavigationStore to share objects from one state to the next state

Toolkit.Avalonia/ITransientNavigationStore.cs

@@ -0,0 +1,15 @@
+namespace Toolkit.Avalonia;
+
+public interface ITransientNavigationStore<TControl> 
+    where TControl : class
+{
+    void Clear();
+
+    T? Get<T>(TControl control)
+           where T : class;
+  
+    void Remove(TControl control);
+
+    void Set(TControl control,
+        object parameters);
+}