Rework bosses to be a time sensitive clan event

[Zenoo]

• Button to start a boss fight (master for now, permission tied later)
• Clicking on it creates a BossFight and redirects to a boss fight view
• Open a WebSocket on that view that is only allowed if an existing BossFight exists for the current clan
• Load Pixi with the boss arriving
• The boss will attack every 10-30s and damage the clan HP
• Every brute has X actions to use, some definite, some with a cooldown (ex: hit boss, meat shield, buff, etc ...), skills can be manually used, same for weapons
• Only one action per clan every X seconds
• When a brute acts, its sprite gets generated or reused from previous action. Unload sprites between actions to prevent lag
• Fight ends when clan HP drops to 0 or boss HP drops to 0
• Limit to 1 fight per week