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.Editor/View/Windows/EngineEditorWindow.xaml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<winex:WindowEx
+    x:Class="Ghost.Editor.View.Windows.EngineEditorWindow"
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+    xmlns:local="using:Ghost.Editor.View.Windows"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    xmlns:winex="using:WinUIEx"
+    Title="EngineEditorWindow"
+    mc:Ignorable="d">
+
+    <Grid />
+</winex:WindowEx>