* Add ability to sync all LINE contacts, which is relevant because the
list of recent chats excludes users you haven't spoken to lately.
* Add bot command to list all contacts.
* Allow inviting a puppet to a DM to create a portal for that LINE user,
instead of having to wait for that user to message you first.
* 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
* 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
1. Don't set the "own message" promise to null on resolve, as other
places may still be awaiting on it afterwards
2. Retry pressing "Enter" to send a message if it doesn't work on the
first try, which can happen for some reason
Even if Chrome is the only window in an X session, and even if the
window is focused, the LINE extension stops getting new messages unless
the mouse has moved recently. To work around that, use xdotool to move
the mouse every so often.