Lacks support for WebGPU accelerated backend

[MagnusThor]

Add WebGPU accelerated WebGPU backend to TensorFlow.js using tensorflow/tfjs-backend-webgpu

[MagnusThor]

Manage to get this is place, seems like the glsl/wgsl shader must be adjusted as well as the settings, masks etc, depending in backend. I look futher into this when trying to implement body-segmentation/selfie_segmentation