Python: Copy Python extractor to codeql repo

python/extractor/tox.ini

@@ -0,0 +1,15 @@
+[tox]
+envlist = py37, py38, py39, py310, py311, py312
+minversion = 4.11.3
+isolated_build = true
+
+[testenv]
+skip_install = true
+allowlist_externals = poetry
+commands_pre =
+    poetry env use -- {env_python}
+    poetry install
+commands =
+    poetry run pytest tests/
+setenv =
+    VIRTUALENV_DISCOVERY = pyenv