Remove env parameter from app factory function

{{cookiecutter.repo_name}}/manage.py

{{cookiecutter.repo_name}}/{{cookiecutter.repo_name}}/app.py

...okiecutter.repo_name}}/{{cookiecutter.repo_name}}/main.py

....repo_name}}/{{cookiecutter.repo_name}}/modules/public.py

...cutter.repo_name}}/{{cookiecutter.repo_name}}/settings.py

...po_name}}/{{cookiecutter.repo_name}}/tests/test_models.py