Add cooldowns to commands on items

[ghost]

For example, if you use the 'god-ring', it can have a configurable cooldown so it cannot be spammed.

[KnifeKat]

Might be good to extend this to slots in the RPGInventory as well.

Example: We have a Command attached to the information button that warps them to their home. It can be used infinite times, as many times as they want, without a cooldown.

If this was possible to make it have a cooldown, we could give players the choice to teleport home once every hour instead. Since this is not possible currently, we've set to use an item to do it instead unless its added to rpginv.