Add raytracing pipeline support to rendersystemvulkan & vfx_vulkan * Add UtlVector::ByteCount(), UtlVector::EnsureCountZeroed( int num ) * rendersystemvulkan: support raytracing pipelines * vfx / vfx_vulkan: support compiling rtx shader blocks targeting vulkan 1.2 * CRayTraceSceneWorld without lights for now