Add support to provide configurable key mappings

[Boubalou]

📖 Description

Change the hardcoded key mapping and select key to the global configuration, allowing integrator to provide their own sets of custom key mapping.

This is mandatory to work on Xbox one with the game controller, for instance.

Example of the key mapping to provide to support Xbox one:

var selectKeyCodes = [13, 195];

var keyMapping = {
  '37': 'left',
  '205': 'left',
  '38': 'up',
  '203': 'up',
  '39': 'right',
  '206': 'right',
  '40': 'down',
  '204': 'down'
};

SpatialNavigation.set({keyMapping, selectKeyCodes})