First phase of refactoring atom thumbnail and preview rendering into a reusable system that can be used for additional thumbnail types and capturing preview images for other purposes. Our

• Removed classes for initialization and teardown steps of the renderer
• Moved initialization and teardown logic back to the renderer constructor and destructor
• Combined thumbnail render context and data with the main renderer class
• Made all render data private and instead implemented a public interface
• Remaining steps were simplified and updated to work directly with the new public interface
• Changed the waiting for assets to load state to poll asset status on tick because we were timing out there anyway
• Unified redundant camera configuration variables and made sure they were used consistently when initializing and updating the scene and camera
• Changed interface for custom feature processor request API to build a set instead of returning a vector
• Moved initialization of the thumbnail renderer and preview factory after asset catalog has loaded

Signed-off-by: Guthrie Adams <guthadam@amazon.com>

Gems/AtomLyIntegration/CommonFeatures/Code/Source/EditorCommonFeaturesSystemComponent.h

@@ -28,6 +28,7 @@ namespace AZ
             , public AzToolsFramework::EditorLevelNotificationBus::Handler
             , public AzToolsFramework::SliceEditorEntityOwnershipServiceNotificationBus::Handler
             , public AzToolsFramework::AssetBrowser::PreviewerRequestBus::Handler
+            , public AzFramework::AssetCatalogEventBus::Handler
             , public AzFramework::ApplicationLifecycleEvents::Bus::Handler
         {
         public:
@@ -56,6 +57,9 @@ namespace AZ
             void OnSliceInstantiated(const AZ::Data::AssetId&, AZ::SliceComponent::SliceInstanceAddress&, const AzFramework::SliceInstantiationTicket&) override;
             void OnSliceInstantiationFailed(const AZ::Data::AssetId&, const AzFramework::SliceInstantiationTicket&) override;
 
+            // AzFramework::AssetCatalogEventBus::Handler overrides ...
+            void OnCatalogLoaded(const char* catalogFile) override;
+
             // AzToolsFramework::AssetBrowser::PreviewerRequestBus::Handler overrides...
             const AzToolsFramework::AssetBrowser::PreviewerFactory* GetPreviewerFactory(const AzToolsFramework::AssetBrowser::AssetBrowserEntry* entry) const override;