Converted preview renderer to use AZ::Interface

Made some files private when exposing public interfaces
Updated a few comments

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

Gems/Atom/Tools/AtomToolsFramework/Code/Source/AtomToolsFrameworkModule.cpp

@@ -10,6 +10,7 @@
 #include <AtomToolsFrameworkSystemComponent.h>
 #include <Document/AtomToolsDocumentSystemComponent.h>
 #include <Window/AtomToolsMainWindowSystemComponent.h>
+#include <PreviewRenderer/PreviewRendererSystemComponent.h>
 
 namespace AtomToolsFramework
 {
@@ -19,6 +20,7 @@ namespace AtomToolsFramework
                 AtomToolsFrameworkSystemComponent::CreateDescriptor(),
                 AtomToolsDocumentSystemComponent::CreateDescriptor(),
                 AtomToolsMainWindowSystemComponent::CreateDescriptor(),
+                PreviewRendererSystemComponent::CreateDescriptor(),
             });
     }
 
@@ -28,6 +30,7 @@ namespace AtomToolsFramework
             azrtti_typeid<AtomToolsFrameworkSystemComponent>(),
             azrtti_typeid<AtomToolsDocumentSystemComponent>(),
             azrtti_typeid<AtomToolsMainWindowSystemComponent>(),
+            azrtti_typeid<PreviewRendererSystemComponent>(),
         };
     }
 }