scripts: Add object type enum generation to helper
scripts: Add object type enum generation to helper

Extended the helper_file_generator to produce an object type enum
header file.

Change-Id: I8013091b34028522d8f50ef3941d7021b262613c

KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools