Rewrite tilesets option/config

[zzolo]

Need to make the tilesets option to be more flexible and standard instead of just handling Bing differently. Something like:

{
  'tileset name': {
    type: 'TileLayer',
    attribution: 'Some attribution',
    preview: 'https://example.com/image',
    arguments: [
      'https://{s}.maps.com/{x}/{y}/{z}.png',
      {  options }
    ]
  }
}