Farm Gate Keys

Adds a shared farm key system for standard animated doors, hall gates and fence gates.

Features:
- Locked gates/doors cannot be opened.
- All players of the same farm share the same key.
- Lock / unlock is only available while standing in the trigger.
- Locking is only possible while the gate / door is fully closed.
- Hooks globally into standard AnimatedObject / AnimatedMapObject controls.

Default key binding:
- ALT + E = Lock / unlock gate or door
- Controller: Square = Lock / unlock gate or door (note: currently not fully reliable)