Snow on Stairs [datapack]

- Optimized the amount of models files and reorganized both the datapack and the resourcepack folders structure
- Removed the snow drop when breaking a "snow-logged" block. It will now only drop the block, not the snow too
- When breaking a "snow-logged" block, the snow breaking sound will now play
- Updated the list of snowable blocks to include missing blocks from recent updates
- Added a new item tag `snow_on_stairs:snowable` to search all snowable blocks inside the Creative Inventory