Better Cooldowns

Cooldowns are a bit limited rn, causing people to use jank alternatives like auras

I think there could be some improvements to make them more versatile:

• A CooldownSkills option in skills

Ability:
  Cooldown: 3
  CooldownSkills:
  - message{m="This is on cooldown!"} @self
  Skills:
  - a

• A <skill.var.cooldown> placeholder

Ability:
  CooldownSkills:
  - message{m="This is on cooldown! (<skill.cooldown.remaining.seconds>s remaining, <skill.cooldown> max)"} @self

• Global cooldown skills

# Config.yml
DefaultCooldownSkill:
  - message{m="This is on cooldown! (<skill.cooldown.remaining.seconds>s remaining, <skill.cooldown> max)"} @self