Install from wheel

I build gvec_to_python via pip install build; python -m build and got the .whl file, then installed it. However, there were no dependencies installed. Should we move them from requirements.txt to setup.py to make that work?

assigned to @g-tinkei

closed with commit 46d1b93b

The option install_requires is now included in setup.cfg. A dummy setup.py is also added.