Allow players to showcase their wares at Troll's Haven

[brightrim]

Functionality (already coded):
Allow players to talk to an npc to put an item they want to showcase on a nearby display table for a certain duration, at a cost. Said item will show who put it up for display. Said item will also later be returned to the player, either by delivery or pick up(tbd).

Missing:
@slightlycomatose will create and designate which npc is meant to have the functionality, as well as which and how many tables are to be used for the showcasing.
German translations are also still needed after that.