Re-add Lootables

[qlados]

This feature was introduced when Lifeboat was a thing to allow the creation of Survival Games/Skywars maps. However I think that it has utility beyond those gamemodes and should be reintroduced to the plugin at some point.

Reference: http://docs.oc.tc/modules/lootables

[Pablete1234]

This is still a missing feature that should eventually come back

[KingOfSquares]

This can be closed(lets go) #1044