FastShop - Unique shop system v1.3.6

1. Fixed the inventory error thrown on Folia.

1. Fixed sounds not playing

1. Made it so you can add an icon that executes commands.
2. Added buy price lore in config.
3. Added sell price lore in config.
4. Fixed the /shopitem command.
5. You can now disable the sell command through config.

1. Fixed the Folia Support.
2. Fixed it not having next page.

1. Fixed not showing sell price if it's below 1.
2. Fixed not showing buy price if it's below 1.

1. Made it so you can change rows.
2. Added ability to sell.
3. Added sell GUI.
and more..

1. Added a logger when selling items, so everything is in logs in case of need (Optional).

1. Made the +16 and -16 add up correctly.
2. Fixed empty space count based on the item you're buying.