Synthetic collection generation

docs/assets/screenshots/synthetic_blob_slices.png

docs/assets/screenshots/synthetic_collection_cc.gif

docs/assets/screenshots/synthetic_collection_default.gif

...ssets/screenshots/synthetic_collection_default_labels.gif

docs/generate.md

docs/processing.md

docs/utils.md

mkdocs.yml

qim3d/__init__.py

qim3d/generate/__init__.py

qim3d/generate/blob_.py

qim3d/generate/collection_.py

qim3d/gui/annotation_tool.py

qim3d/processing/__init__.py

qim3d/processing/operations.py

qim3d/processing/structure_tensor_.py

qim3d/utils/__init__.py

qim3d/viz/structure_tensor.py