restructring examples (#909)

* restructring examples

* modifications to titles/paths

* cleanup
Co-authored-by: root <root@rocm-framework-3.amd.com>

examples/vision/README.md

+# Vision Inference Examples
+
+- [CPP MNIST](./cpp_mnist)
+- [Python Resnet50](./python_resnet50)
+- [Python Super Resolution](./python_super_resolution)
+- [Python NFNet](./python_nfnet)
+- [Python U-Net](./python_unet)
+- [Python 3D-UNet](./python_3dunet)
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