Adds /paper command for reloading the paper config.
Closes GH-639
Per-world config logging has been removed in favor of all or nothing
logging for all paper settings. I don't believe it was used enough to
warrant maintaining. If this is not the case it should be possible to
re-add it.
Servers behind a bungeecord proxy in offline mode
will now properly pull offline mode UUIDs and data
when this setting is set to false. Default is unchanged.