Allow refund for Tickets/Books

Suggestions
1

Imported from legacy Flarum.
Original author: StellarFlare (Flarum #319)

Let us sell back those items to the npc for the same price we bought it for. Bought the wrong ticket by mistake or saw you don’t meet the reqs? Sell it for your money back. Saw you got too many enchant books? Sell it back and fix your life.

2

Imported from legacy Flarum.
Original author: Muh (Flarum #1)

We expect players to think about their purchases. If something is bought by mistake there’s still an option to trade it to other players.