Add Looting-Based Stacked Entity Sell Feature + VIP Sell Bonus

[ShizenXDD]

Implement a feature that allows selling stacked entities with value scaling based on the Looting enchantment level. Additionally, introduce a percentage-based sell bonus for VIP players to incentivize rank upgrades and enhance gameplay rewards.
Suggested Implementation Details:

• When selling stacked entities (e.g., mobs), calculate the total value using the Looting level of the killing item.
• Apply a configurable percentage bonus to the final sell value for players with VIP ranks.
• Ensure compatibility with existing economy and stacking systems.
  This feature would improve monetization for players and add depth to farming/grinding mechanics.

[ShizenXDD]

@OmerBenGera

[OmerBenGera]

@OmerBenGera

I am not gonna implement it as of now, but PRs are more than welcomed :)

[ShizenXDD]

It would be great if you added it, I'm desperate lol