Implement VK_LAYER_LUNARG_assistant_layer

Phoenix supports validation layers when built in debug mode.  Adding the LunarG Assistant Layer would help orient dev users toward Vulkan best-practices.

See this doc and Github Issue for more details:

https://www.lunarg.com/vulkan-assistant-layer-highlights-best-practices/
https://github.com/KhronosGroup/Vulkan-LoaderAndValidationLayers/issues/1612