Remove pytest.ini in favor of setup.cfg

Temporary before pyproject.toml see,
https://docs.pytest.org/en/stable/customize.html#setup-cfg
diff --git a/setup.cfg b/setup.cfg
index 0ad92d3..d8865ba 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -61,3 +61,8 @@
 
 [tool:pytest]
 testpaths = tests
+python_files=*test_*.py
+addopts=-m "not acceptance"
+markers =
+   acceptance:
+   benchmark: Baseline of pylint performance, if this regress something serious happened