Add options for spawners to drop items

[daltonsbiscord]

So have a configurable settings that instead of spawning in mobs, a spawner will spawn in the drops the mob would have when killed, this would be helpful for bigger servers with a lot of people with spawners causing a lot of entities and help reduce the amount of lag.

[Esophose]

https://github.com/Rosewood-Development/RoseStacker/blob/master/Plugin/src/main/java/dev/rosewood/rosestacker/event/PreStackedSpawnerSpawnEvent.java