C++ Bindings

[vetschn]

After bit of evaluation it seems like C++ bindings using nanobind with a CMake build system are a sensible/straightforward option. The idea should be to realize the most demanding and repetitive computations (e. g. matrix multiplications and index computations) in the C++ back-end.

• Set up the build system
• Implement C++ routines
  • matmul
  • conversion routines
  • validation routines
• Link to the generated library in the Python front-end