method to get the container on the current tile

doesn't handle multiple containers on a tile yet
track the locked state of containers
pass through arguments to the publisher
allow using the unlock action to unlock containers
track container items, and pick them up if possible
more prompts and messages about locking containers
remove the item from the container, not the floor
hack around propagating the container along

no idea how to do this properly, we send the action to loot the
container, but then the screenscraper on the next input cycle doesn't
know what container it's coming from. just assume that it's the
container on the current tile for now, but we'll need to fix this to
loot from our inventory