Feature: Add sounds for doors & item pickups

[pushfoo]

Interacting with objects like doors, ladders, and item pickups is more satisfying for players if the action plays a corresponding sound.

The following actions in this RPG could be improved by adding corresponding audio:

• Picking up apples from the basket in the house
• Picking up the dagger from the cloth-covered pot in the dungeon
• Using the doors to enter and exit the house
• Moving up and down the ladder to the dungeon found in the hole in the graveyard

Most of the actions in this list have reasonable matches in Kenney's RPG Audio pack. For the ladder sounds, a number of clips could be played one after another, or an audio editing program could be used to create a sound.

The sound files should be placed in a directory under resources.

Since the RPG Audio pack is licensed under a CC0 1.0 Universal Public Domain Dedication, there are no licensing restrictions on the sounds at all. However, It would still be polite to cite the source.