Refactor project structure and enhance functionality

Added `InternalsVisibleTo` attribute for "Ghost.Editor" in `AssemblyInfo.cs`.
Added a binary file `Empty.zip` to the project.
Added a new `ProjectMetadata` class in `ProjectMetadata.cs`.
Added new states and interfaces for managing application states in `EditorState.cs`, `LandingState.cs`, and `IAppState.cs`.
Added a notification service in `INotificationService.cs` and `StackedNotificationService.cs`.
Added new XAML files for UI components, including `InspectorView.xaml` and `InternalControls.xaml`.

Changed the `ProjectInfo` class in `ProjectInfo.cs` to include a `MetadataPath` property instead of `Path` and `EngineVersion`.
Changed the `TemplateInfo` class in `TemplateInfo.cs` to use a struct instead of a class for `TemplateData`.
Changed the `ProjectService` class to use the new `ProjectRepository` for managing project data.

Removed several using directives and the entire `ProjectRepository` class from `ProjectRepository.cs`, replacing it with a new implementation.
Removed old methods and properties in `EntityManager` and `World` classes to improve entity management and component handling.

Updated the `Ghost.Data.csproj` file to include the new `Empty.zip` file as a content item.
Updated the `ProjectRepository` class to manage project data using SQLite.
Updated various XAML files to include new styles and controls, improving the overall UI design.
Updated the `CreateProjectViewModel` to include a notification service and handle project creation logic.
Updated the test project to include references to the new `Ghost.Graphics` project and modified test cases to align with the new structure.

Ghost.Editor/View/Pages/EngineEditor/ProjectPage.xaml

@@ -0,0 +1,71 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<Page
+    x:Class="Ghost.Editor.View.Pages.EngineEditor.ProjectPage"
+    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.Pages.EngineEditor"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    mc:Ignorable="d">
+
+    <Grid Background="{ThemeResource LayerFillColorDefaultBrush}">
+        <Grid.ColumnDefinitions>
+            <ColumnDefinition Width="250" />
+            <ColumnDefinition Width="*" />
+        </Grid.ColumnDefinitions>
+
+        <!--  Folder Tree View  -->
+        <Grid
+            Grid.Column="0"
+            BorderBrush="{ThemeResource CardStrokeColorDefaultSolid}"
+            BorderThickness="0,0,1,0">
+            <TreeView
+                HorizontalAlignment="Stretch"
+                VerticalAlignment="Stretch"
+                Background="{ThemeResource CardBackgroundFillColorSecondaryBrush}"
+                ScrollViewer.HorizontalScrollBarVisibility="Disabled"
+                ScrollViewer.VerticalScrollBarVisibility="Auto">
+                <TreeView.ItemContainerStyle>
+                    <Style TargetType="TreeViewItem">
+                        <Setter Property="Padding" Value="4,2" />
+                        <Setter Property="Margin" Value="0,0,0,2" />
+                    </Style>
+                </TreeView.ItemContainerStyle>
+            </TreeView>
+        </Grid>
+
+        <!--  Files  -->
+        <ScrollViewer
+            Grid.Column="1"
+            HorizontalScrollBarVisibility="Auto"
+            VerticalScrollBarVisibility="Auto">
+            <GridView HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
+                <GridView.ItemContainerStyle>
+                    <Style BasedOn="{StaticResource DefaultGridViewItemStyle}" TargetType="GridViewItem">
+                        <Setter Property="Margin" Value="5,5,5,5" />
+                    </Style>
+                </GridView.ItemContainerStyle>
+
+                <GridView.ItemTemplate>
+                    <DataTemplate>
+                        <Grid>
+                            <Grid.RowDefinitions>
+                                <RowDefinition Height="*" />
+                                <RowDefinition Height="0.2*" />
+                            </Grid.RowDefinitions>
+                            <ImageIcon
+                                Grid.Row="0"
+                                Width="24"
+                                Height="24" />
+                            <TextBlock
+                                Grid.Row="1"
+                                Margin="8,0"
+                                VerticalAlignment="Center"
+                                TextTrimming="CharacterEllipsis" />
+                        </Grid>
+                    </DataTemplate>
+                </GridView.ItemTemplate>
+            </GridView>
+        </ScrollViewer>
+    </Grid>
+</Page>