Adds:
- Company's chest shop
- The member of the company can now create the chest shop.
- The employer cannot disband the company without removing all the shops.

Changes:
- The supported versions are changed to 1.20+ from 1.16+

How to create chestshop:
1. Placing a chest, with a hopper connecting. (The destination of the hopper should be the chest)
2. Placing a wall sign in front of the chest
3. Enter the text for sign like this:
- line1: [COMPANYSHOP]
- line2: PRICE (example: 50)
4. The sign will be updated if it the input amount is valid
5. As the product for sale of the shop is not specified, you need to put 1 of product to the hopper, and letting it move to the chest.
6. Item specified! Other players can buy the product!