Use TextureAtlasLayout instead of using your own solution for this

[evilenzo]

Currently atlas textures work are handled by this lib and configured using TileTextureIndex. But bevy already has solution for such case and it's the TextureAtlasLayout. It's way more configurable cause it allows you to use offsets and paddings in atlas textures.
Profits we get from that:

• Support one less thing in library by using standard way bevy provides (it makes even more sence since author of this lib wants it to be included into bevy)
• More configuration options solving some problems