docs: Unify doc and git READMEs

README.rst

+docs/README.rst
\ No newline at end of file

docs/index.rst

 .. _swh-py-template:
 
-Software Heritage - Python module template
-==========================================
-
-Python module template, used as skeleton to create new modules.
-
+.. include:: README.rst
 
 .. toctree::
    :maxdepth: 2

setup.py

@@ -12,7 +12,7 @@ from setuptools import find_packages, setup
 here = path.abspath(path.dirname(__file__))
 
 # Get the long description from the README file
-with open(path.join(here, "README.md"), encoding="utf-8") as f:
+with open(path.join(here, "README.rst"), encoding="utf-8") as f:
     long_description = f.read()