Interact with map objects

[cxong]

Add the ability to interact with map objects using the switch/slide key. When the player is up close against a map object, a text prompt will appear, like ": use". Example scenarios:

• Non-gameplay effects, like computers beeping, switching lights on/off
• Opening boxes/lockers; can result in adding pickups in front of the box
• New objective type, to interact with a map object. This can be written as "access mainframe", "plant tracking device", "check for contraband" and so on
• Unlocking doors, by having the interaction mimic picking up a key
• As a crude turret (Vehicles, turrets #30) or triggered trap; interaction to cause a gun attached to the map object to fire

Each of these scenarios may require some work, so we can start with just one, for example non-gameplay effects. This includes:

• Marking that a map object can be interacted with, and the interaction type
• Sound to play on interaction
• Play a specific animation for the map object. We already have animated map objects (Animated map objects #430 ) but this is only the one animation, we will need to add multiple animations per map object, and whether the end animation event (loop? or go back to idle animation?)