Fill Hole

Changes:

• Modify the fillhole command to use Bukkit tasks, allowing larger region sizes without crashes.
• Optimize the fillhole command for better performance.
• Replace max_valid_blocks with max_selection_size for consistency.

Features:

• Add auto-reload for the configuration, with a reload_delay option (default: 5 minutes).
• Add task control settings in the config:
  • filter_processed_cycle
  • filter_tick_cycle
  • fill_hole_processed_cycle
  • fill_hole_tick_cycle
• Add a progress bar to track the completion of the fillhole command.