Cooldown variable in buttonresponders#552

The ability to add a cooldown to BR will make it so it “disables” the button for each user after a single use. I stumbled across the lack of the cd variable when I was trying to make a giveaway BR. And the limitations would disable the button entirely if on limited/strict, not allowing for it to only disable for the user that presses it and leaving it available for other members to also press….once. I think this addition (or adding a new type of limitation) would grow the usage of button responders to a new level c: