feat(core) add MemoryUtil.memByteBuffer(Struct)

[httpdigest]

What already works: View a Struct.Buffer as a ByteBuffer:

uploadBuffer(
  memByteBuffer(
    // VkAccelerationStructureInstanceKHR.Buffer
    VkAccelerationStructureInstanceKHR
      .calloc(1, stack)
      .accelerationStructureReference(blasDeviceAddress)
      .mask(~0)
      .flags(...)
      .transform(...)
  )
);

What this PR is adding: View a single Struct as a ByteBuffer:

uploadBuffer(
  memByteBuffer(
    // VkAccelerationStructureInstanceKHR
    VkAccelerationStructureInstanceKHR
      .calloc(stack)
      .accelerationStructureReference(blasDeviceAddress)
      .mask(~0)
      .flags(...)
      .transform(...)
  )
);