Changes include:
* Remove target unit
* Create and use config directory
* Use directory directly under /opt as home
* Rename suggested user/group
* Restart on failure
* (aside) Rename Node module name after Chrome unit
* Update Dockerfiles to work properly
* Use latest available version of Alpine Linux
* Update Puppeteer to 9.1.1 to match Chrome version available in latest
Alpine Linux
* Add docker script for Node process to allow custom config
* Provide separate example config for running Node in docker
TODO: Update SETUP.md with Docker instructions