Door implementation

[DAWacker]

Door are first introduced in level 6 and there isn't a class to load these. This will be pretty simple to implement, but my concern is how we deal with the door shutting. Do we end the game when the door shuts or when the scientist hits the door?

[rxc4763]

When the door locks, the player will get the option to either reset the
level, or quit the game.

[DAWacker]

@rxc4763 👍