This PR moves the ownership of vulkan memory allocator from gpu/device to GHOST/context/device. This will allow in the future a cleaner control flow between OpenXR and Vulkan. Currently as the ownership is in the gpu module many objects would need to pass from GHOST to the GPU module to be shared between the 2 allocators. Moving both (OpenXR/Context) allocator to GHOST would reduce the complexity. Pull Request: https://projects.blender.org/blender/blender/pulls/146819