Replace the Vulkan-Hpp submodule with Vulkan-Headers

[Macdu]

Hello, first of all thank you very much for these bindings that are really useful to keep vma code consistent with vulkan cpp code. I'm using these bindings for a quite big project which is initialized using: git submodule update --init --recursive

The issue with this repository is that one of its submodule is Vulkan-Hpp which in turn has many useless dependencies (glfw, glm, glslang, tinyxml). From what I understand this repository is aimed to be used directly by the user, in this case only the Vulkan-Headers submodule would be necessary as it contains the Hpp Vulkan bindings and no other dependencies.

I understand that the Vulkan-Hpp submodule may be needed to generate the bindings, so it's up to your choice to keep or not this module. Right now I am using a fork with this submodule removed.