Implement the ability to stop a currently running game

[mdaffin]

The game needs a way for layers to quit or stop the game. This should be an extra endpoint that players can call and it should return final game state data so they can see how well they have done.

It should include:

• the time it took to complete the maze (or the game is stopped)
• the moves the player took
• the whole map
• a flag to indicate success or failure