Restore being able to prop another user who is not the current DJ

[FranciscoG]

When I first started the bot the code (which I forked) had the ability to prop any user at any time. There was a hardcoded command !prop which you could add a user name to !prop whosywhatsitand it would prop that user. I removed that hard coded command but there wasn't a good way to implement user propping through the trigger props. I think the easiest way is to restore the hardcoded!prop` back.