Add support for DeviceAndHost memory

[robquill]

This is a new memory type with these Vulkan flags set:

    case MemoryTypes::eDeviceAndHost:
        return vk::MemoryPropertyFlagBits::eDeviceLocal |
               vk::MemoryPropertyFlagBits::eHostVisible |
               vk::MemoryPropertyFlagBits::eHostCoherent;

It means that a copy between staging and primary memory is not required because the device memory is also host-visible and host-coherent. This type of memory allocation may not be supported on all platforms/devices, but if they do support it it can improve performance by avoiding an unnecessary copy.

[axsaucedo]

Interesting, this would make examples much smaller and more intuitive - LGTM!