Removes unused files like requirements.txt, setup.py, and setup.cfg. Now we only use pyproject.toml. Includes .flake8 as a replacement for setup.cfg.
Updates the documentation to install the package. requirements.txt file is obsolete and the only way to install this package from the source is by using pyproject.toml.
This PR:
requirements.txt,setup.py, andsetup.cfg. Now we only usepyproject.toml. Includes.flake8as a replacement forsetup.cfg.requirements.txtfile is obsolete and the only way to install this package from the source is by using pyproject.toml.Related to https://github.com/chaoss/grimoirelab/issues/532