Consolidate glTF PBR graph and remove GLSL override#2850

jstone-lucasfilm merged 1 commit intoAcademySoftwareFoundation:mainAcademySoftwareFoundation/MaterialX:mainfrom

jstone-lucasfilm:dev_gltf_pbrjstone-lucasfilm/MaterialX:dev_gltf_pbrCopy head branch name to clipboard