Add item groups config

[mani1232]

For example
item_groups:
axes:
- slot:hands
- wooden_axe
- stone_axe
- iron_axe
- golden_axe
- diamond_axe
- netherite_axe

books:
- book
- enchanted_book

pickaxes:
- slot:hands
- wooden_pickaxe
- stone_pickaxe
- iron_pickaxe
- golden_pickaxe
- diamond_pickaxe
- netherite_pickaxe