Shulker's Faithful Factories

Added Shulker Factories - a new heavily guarded structure which generates at ~1/10th the rate of end cities, but has several items of interest to a redstoner including:

• -Dragon Eggs (rare)
• -Shulkers (both the type that shoots at you, and the type with randomly generated loot!)
• -Redstone components
• -Enchanted elytras (rare)
• -Traps
• -Lore. Sort of. There's no written text, but it's there.
• ....and most importantly....
• -A shulker spawner!