Mob Variants

!!! BACKUP YOUR CONFIG BEFORE UPDATING !!!

• removed corsairSpawnWithSwordChance option
• removed undeadWarriorSpawnWithSwordChance option
• added alwaysKeepEnchantedBow option to undead warrior's attributes (when true, undead warriors keep the enchanted bow instead of trying to replace it)
• added options to customize mob's equipment for:
  • undead warrior
  • corsair
  • soul stealer
  • executioner
• executioner can now spawn with full iron set (not only 1-2 pieces)
• added missing Haemorrhage compat (spiders apply Health Loss instead of Bleeding)