pytest config sync

[webknjaz]

Port and adapt the pytest.ini from https://github.com/aio-libs/yarl/blob/master/pytest.ini, https://github.com/aio-libs/yarl/blob/master/pytest.ini, https://github.com/aio-libs/frozenlist/blob/master/pytest.ini, https://github.com/aio-libs/propcache/blob/master/pytest.ini, https://github.com/cherrypy/cheroot/blob/main/pytest.ini, https://github.com/ansible/pylibssh/blob/devel/pytest.ini, https://github.com/ansible/awx-plugins/blob/devel/pytest.ini, https://github.com/sphinx-contrib/towncrier/blob/master/pytest.ini. And delete the pytest configuration from setup.cfg.

@aiolibsbot implement