v2.6: HuskTowns at war

[WiIIiam278]

The first part of the v2.6 update will introduce town wars to HuskTowns! Wars will be disabled by default, but server owners can enable them to allow towns to battle it out.

Wars are town-wide events that trust a settlement into action against another settlement. This PR adds:

• The town relations system — towns can now declare other towns allies or enemies. Turned on by default.
  • View and set relations through the /town relations command
  • You can be an ally, neutral (default), or an enemy with any other town
  • A new role privilege has been added for managing this
• Towns can now go to war! Turned off by default.
  • Managed through the /town war command
  • To declare war, towns must be mutual enemies of each other
  • You can wager money from your town coffers on wars; the victor will get the sum of both wagers added to their coffers afterwards.
  • If the defending town accepts the terms of the war declaration, the defending town will be teleported to their town spawn. The attacking town will be teleported to the outskirts of the defending town.
  • Online players from both towns must now battle it out to be the last man standing. Players are removed from war if they die, or leave the "war zone radius" around the defending town's spawn
  • Special flag rules apply in the defending town during town wars. Depending on how brutal you want wars on your server to be, you can enable building/griefing within towns.
  • A new role privilege has been added for declaring/accepting declarations of war.
• The online player state of towns is now tracked and displayed again in the town census menu (as it was in v1!).
  • More accurate if you're using Redis (recommended especially if you're using the War system)