Refactor project structure and enhance functionality

Changed the project namespace from `Ghost.Editor` to `Ghost.App` across multiple files.
Changed the `InternalsVisibleTo` attribute in `AssemblyInfo.cs` to include `Ghost.App`.
Changed the `ProjectRepository` class to add new asynchronous methods for retrieving projects by ID, name, and metadata path.
Changed the `ProjectService` class to utilize the new asynchronous project loading methods.
Changed the `SceneGraph` classes to improve node management and serialization.
Changed the `EntityManager` class to enhance entity management with new component handling methods.
Added new test classes, `EntityTest` and `SerializationTest`, to ensure reliability in entity and serialization systems.
Added the `Ghost.App` project file to establish a modular project structure.
Added the `Ghost.Generator` project for automated component serialization code generation.
Updated UI components to reflect the new namespace for proper functionality.

Ghost.InternalEditor/Utilities/Converters/GetDirectoryNameConverter .cs

@@ -0,0 +1,17 @@
+using Microsoft.UI.Xaml.Data;
+using System;
+
+namespace Ghost.Editor.Utilities.Converters;
+
+public partial class GetDirectoryNameConverter : IValueConverter
+{
+    public object? Convert(object value, Type targetType, object parameter, string language)
+    {
+        return value is string path ? System.IO.Path.GetDirectoryName(path) : null;
+    }
+
+    public object? ConvertBack(object value, Type targetType, object parameter, string language)
+    {
+        throw new NotImplementedException();
+    }
+}