Use pyproject.toml, replace setup.cfg and setup.py

[benjaoming]

This project can use https://github.com/pypa/build

We should migrate all logic from setup.cfg and setup.py to pyproject.toml.

• The release command in Makefile should be updated.
• Instead of from wiki import __version__, we need to hard-code the version string in pyproject.toml

Nice-to-have:

• A tool to bump versions