Feature: onnx integration

[fortmeier]

Add creation of compute graph nodes from a ONNX file.
The first example that is integrated is https://github.com/onnx/models/tree/main/validated/vision/super_resolution/sub_pixel_cnn_2016

• Add compute graph group class that encapsulates ONNX loading and processing
• Add code for processing the ONNX graph into klartraum compute nodes (these are for now Conv, Relu, Reshape, Transpose)
• Add tests and shader code for the nodes
• Load and process an example image
• Cleanup and document