Cooldown system

[crejk]

Create cooldown system.
For example:

final Cooldown<?> cooldown = new Cooldown<>();
final ? key;
cooldown.isOnCooldown(key); //boolean - return true if [obj] is on cooldown
cooldown.put(key, 5); //add cooldown(put to cooldown map)(time in seconds)
cooldown.put(key, 5, TimeUnit.MINUTES);
cooldown.putIfAbsent(key, 5); //put if 'isOnCooldown' return false
cooldown.putIfAbsent(key, 5, TimeUnit.MINUTES);
cooldown.ifAbsent(key, () -> { //run runnable if 'isOnCooldown' return true
});
//more...