Refactor activation handling and introduce entity system

Added new `ActivationHandler` class for folder initialization.
Added `ProjectService` class for project-related operations.
Added `Ghost.Entities` project with entity management classes.
Added `EngineEditorWindow` for enhanced user interface.

Changed project files to restructure dependencies and remove unused references.
Changed `ProjectRepository` to use asynchronous methods for improved performance.
Changed data binding in `CreateProjectPage.xaml` and `OpenProjectPage.xaml` to use new data models.
Changed `App.xaml.cs` to utilize the new `ActivationHandler` and include additional services.

Removed `IActivationHandler` interface and integrated its functionality into `ActivationHandler`.
Removed `EditorActivationHandler` as its functionality was merged into `ActivationHandler`.

Updated `AssemblyInfo.cs` to include global using directives for entity types.
Updated image assets to reflect visual resource changes.

Ghost.Data/Models/ProjectInfo.cs

@@ -0,0 +1,32 @@
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace Ghost.Data.Models;
+
+public class ProjectInfo
+{
+    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
+    public int ID
+    {
+        get; set;
+    }
+
+    public required string Name
+    {
+        get; set;
+    }
+
+    public required string Path
+    {
+        get; set;
+    }
+
+    public required Version EngineVersion
+    {
+        get; set;
+    }
+
+    public required DateTime LastOpened
+    {
+        get; set;
+    }
+}

Ghost.Data/Models/TemplateInfo.cs

@@ -0,0 +1,44 @@
+namespace Ghost.Data.Models;
+
+public class TemplateInfo
+{
+    public required string Name
+    {
+        get; set;
+    }
+
+    public string? Description
+    {
+        get; set;
+    }
+
+    public required Version TemplateVersion
+    {
+        get; set;
+    }
+
+    public required Version EngineVersion
+    {
+        get; set;
+    }
+}
+
+public class TemplateData(string templatePath, TemplateInfo info)
+{
+    private const string _ICON_NAME = "icon.png";
+    private const string _PREVIEW_NAME = "preview.png";
+
+    public string directory = Path.GetDirectoryName(templatePath)!;
+
+    public TemplateInfo Info => info;
+
+    public Uri GetIconURI()
+    {
+        return new Uri(Path.Combine(directory, _ICON_NAME));
+    }
+
+    public Uri GetPreviewURI()
+    {
+        return new Uri(Path.Combine(directory, _PREVIEW_NAME));
+    }
+}