Drop setup.cfg, migrate pytest config to pyproject.toml

pyproject.toml

@@ -90,3 +90,9 @@ module = [
     "pyvisfile.*",
 ]
 ignore_missing_imports = true
+
+[tool.pytest.ini_options]
+markers = [
+    "mpi: test distributed FMM",
+]
+

setup.cfg

-[flake8]
-ignore = E126,E127,E128,E123,E226,E241,E242,E265,E402,W503
-max-line-length=85
-
-inline-quotes = "
-docstring-quotes = """
-multiline-quotes = """
-
-# enable-flake8-bugbear
-
-[tool:pytest]
-markers =
-    mpi: test distributed FMM