Restarting / rerunning the container

[stuartpb]

Right now, if, say, the user accidentally stops and/or rms the plushu-nginx container, that kind of grinds this plugin's world to a halt. It would be better if we checked for the container's existence when restarting, and recreate it if it goes missing.

[stuartpb]

The subcommands allow a user to fix this (or to break it), but they, too, should be overhauled (the modern style guide says command scripts should only parse/sanitize before handing off to a plushook).

[stuartpb]

This is a huge problem in the event that the container stops because the server was restarted. This bug needs to be moved to the top of the list.