Mob Battle 2.8.0

• Adds a perimeter tool:
• Allows creation of a perimeter for mob battles
• Creates an outer and inner perimeter:
  • If mobs are outside the inner but not the outer perimeter they try to walk back in
  • If mobs are outside the outer perimeter they get teleported to the center of the perimeter

For past versions see: https://github.com/Flemmli97/MobBattle/blob/1.21/Changelog.md