Rewriting analyze.sh in Python

../analyze.sh is the old script
src/analyze.sh is the new script
call the old script from the Rosenpass repository's root directory with ./analyze.sh
call the new script:
- in analyze_py/marzipan: nix shell
- src/analyze.sh analyze $repo where $repo is the absolute(?) path to the root directory of the Rosenpass repository.