Use the mouse and pathfinding for movement

This PR removes the keyboard movement and adds moving by the mouse with pathfinding.

## To Do
- [x] show the hand cursor from BQ while in the game
- [x] put the white box around the tile the mouse is over like BQ does
- [x] add a simple "pathfinding" algorithm (we'll add A* later when we add obstructions)
- [x] make movement work to a given coordinate via pathfinding
- [x] show the animated green box on the coordinate the player is moving to
- [x] allow the player to change destination in the middle of pathfinding
- [x] remove the existing keyboard movement