Added ability to convert multiply-nested slices (#1239)

* Addressed feedback from previous PR
* Change missing entity aliases to be deterministic.
When converting slices, this helps produce the same results on multiple reconversions of the same data.
* Exposed the asset filter callback.
This allows the slice converter to specifically load nested slices as opposed to not loading *any* referenced assets.
* Added support for multiply-nested slice instance conversion.

Code/Tools/SerializeContextTools/Application.cpp

@@ -35,7 +35,7 @@ namespace AZ
         Application::Application(int argc, char** argv)
             : AzToolsFramework::ToolsApplication(&argc, &argv)
         {
-            // We need a specialized variant of EditorEntityContextCompnent for the SliceConverter, so we register the descriptor here.
+            // We need a specialized variant of EditorEntityContextComponent for the SliceConverter, so we register the descriptor here.
             RegisterComponentDescriptor(AzToolsFramework::SliceConverterEditorEntityContextComponent::CreateDescriptor());
 
             AZ::IO::FixedMaxPath projectPath = AZ::Utils::GetProjectPath();