Refactor render-engine init to use internal code and templates and deprecate the cookiecutter. #45

The current implementation of render-engine init uses cookiecutter which means that any changes we want to make need to be done in multiple places. We should update render-engine init to build the site from Jinja2 templates and code maintained as part of this repository. The output of running render-engine init should be a fully operational Render Engine site with a basic index.html that congratulates the user on setting up their site.