Kelka backpack's

Adds backpacks that can be improved, thereby increasing the space in your inventory. It also adds achievements.

Types of backpacks:

1. Classic - has the inventory of a regular chest

2. Copper - has 9 more slots than the classic one

3. Iron - has a double chest inventory

4. Golden - it has 80 slots

5. Diamond - it has 96 slots

6. Netherite - it has the largest inventory expansion of 144 slots.