Refactor atlas

This MR refactors gui/hud atlas management. This fixes the issues with pack_format 18 (#111)

Tasks:

• implement VehicleHeartAtlas
• implement HeartAtlas
• implement HungerAtlas
• test with 1.20.2
• tests 😄
• create real uv atlas and not create a lot of small textures that have no match in atlas size
• pack format 19