small fixes / voxelization with quadarature

small bugfixes / new examples

better STL voxelization / PEEC documentation

make the code Python 3.10.0 compatible (was 3.10.12)

ruff linting / Qt6 switch / VTK plot export

fix unicode issues on windows

documentation polishing / Dockerfile

fixes for Jupyter and Qt

examples (time domain and impedance matrix) / lift dependencies

biot-savart can be computed with face or voxel currents