[RPG] Boss encounter

[baiumbg]

• Add a boss type encounter to [p]adventure.

• Add boss monsters - tougher than the usual monster of the same level, but higher chance for items to drop and grant more credits.

• Boss encounters are multiplayer PVE fights. When a boss monster has been chosen at the start of the encounter, the following reactions are added:

  • Start fight - starts the boss fight along with whoever reacted with "Join party"
  • Flee - same as with monster encounters
  • Join party - Adds you to the party of the player that encountered the boss

• Player move order is determined randomly at the start of the fight (similarly to [p]duel)

• When a boss is killed, the credit reward is split evenly between all players that were included in the fight

• All items from the boss' drop table are rolled for. If an item drops, it's distributed randomly to someone who was included in the fight