Fade viz

docs/assets/screenshots/interactive_edge_fading.png

docs/assets/screenshots/operations-edge_fade_after.png

docs/assets/screenshots/operations-edge_fade_before.png

docs/notebooks/Untitled.ipynb

docs/processing.md

docs/viz.md

qim3d/__init__.py

qim3d/processing/local_thickness_.py

qim3d/processing/operations.py

qim3d/viz/__init__.py

qim3d/viz/cc.py

qim3d/viz/detection.py

qim3d/viz/img.py