Create skills 'charges'

[NeumimTo]

• In skilltree config only

   id: "ntrpg:fireball_charges"
   parent: "ntrpg:fireball"
   Settings {
      blablabla
   }
   Charges {
      max-amount: 3
      max-amount_levelbonus: 3
      max-amount_per_str: 3 .....
      cooldown-between-charges: 10000
      cooldown-between-charges_levelbonus: -150
   }
   Recharge-continually: true

What will actually happen on the backend during skilltree initialization:

1. create a bytecode for a skill via asm (similar principe as skill with type of "item-access", "command" etc),
2. When the skill is casted it places a buff (effect) to the caster which tracks remaining charges
3. Player may run the skill "max-amount"th-times before actual skill cooldown is applied

• Charges block:
  max-amount: 3
  recharge-continually: if true the cooldown timer starts counting down when the first execution happen, whenever the cooldown is applied is deceided on the last charge.

• ie cooldown of skill is 10s, the player has 3 charges executes each of them with 5 seconds delay.
  in that case the 3rd charge was depleted 15 seconds after the first charge was used => no cooldown applied