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/Controls/Internal/InspectorView.xaml

@@ -0,0 +1,41 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ResourceDictionary
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:local="using:Ghost.Editor.Controls.Internal">
+    <Style TargetType="local:InspectorView">
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="local:InspectorView">
+                    <Grid>
+                        <Grid.RowDefinitions>
+                            <RowDefinition Height="50" />
+                            <RowDefinition Height="*" />
+                        </Grid.RowDefinitions>
+
+                        <!--  Header  -->
+                        <Grid Grid.Row="0">
+                            <ContentPresenter
+                                HorizontalAlignment="Stretch"
+                                VerticalAlignment="Stretch"
+                                Content="{TemplateBinding Header}"
+                                ContentTemplate="{TemplateBinding HeaderTemplate}" />
+                        </Grid>
+
+                        <!--  Content  -->
+                        <Grid Grid.Row="1">
+                            <ScrollViewer HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto">
+                                <ContentPresenter
+                                    HorizontalAlignment="Stretch"
+                                    VerticalAlignment="Stretch"
+                                    Content="{TemplateBinding Content}"
+                                    ContentTemplate="{TemplateBinding ContentTemplate}"
+                                    ContentTransitions="{TemplateBinding ContentTransitions}" />
+                            </ScrollViewer>
+                        </Grid>
+                    </Grid>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+</ResourceDictionary>