Add python packaging metadata

.gitignore

@@ -2,4 +2,8 @@
 *.sw?
 *~
 .coverage
+.eggs/
 __pycache__
+dist
+*.egg-info
+version.txt

MANIFEST.in

+include Makefile
+include README
+include requirements.txt
+include version.txt

setup.py

+#!/usr/bin/env python3
+
+from setuptools import setup
+
+
+def parse_requirements():
+    requirements = []
+    with open('requirements.txt') as f:
+        for line in f.readlines():
+            line = line.strip()
+            if not line or line.startswith('#'):
+                continue
+            requirements.append(line)
+
+    return requirements
+
+
+setup(
+    name='swh.lister.github',
+    description='Software Heritage GitHub lister',
+    author='Software Heritage developers',
+    author_email='swh-devel@inria.fr',
+    url='https://forge.softwareheritage.org/diffusion/DLSGH/',
+    packages=['swh.lister.github'],
+    scripts=[],
+    install_requires=parse_requirements(),
+    setup_requires=['vcversioner'],
+    vcversioner={},
+    include_package_data=True,
+)