add example node server, rename port variable to make agnostic of server, remove references to php from conig panel.

modify scripts to add node builds, and node systemd service, add node related config, and remove php

Add to try_files to search for files to serve that match the request url plus an additional .html extension.

https://github.com/YunoHost/apps/commit/60d3fbcf03a6a07d100dd2f4af0732a25cb83c8a