UX iterations on ticket tool

[vcarl]

#88 added essential support for a ticketing system using threads, but one thing it doesn't provide is the same "close" experience, allowing the user who opened a ticket to indicate they're done.

What this bot does currently looks like this:

What the old Ticket Tool does looks like this

I think it would be good to add a "close" button. That close button should lock the ticket, remove the person who opened the ticket, and print a message to #mod-log linking to the thread and describing the state change.

It might also be good later on to add some kind of "quality of experience" feedback mechanism to the close interaction 👀