Add per-projectile uncertainty configuration to paper-global.yml

[LoliColleen]

Summary

Adds a projectiles.uncertainty section to paper-global.yml that allows server owners to override the uncertainty parameter passed to Projectile#shoot on a per-entity-type basis.

• Introduces ProjectileUncertainty.resolve(EntityType, float) to look up configured values from GlobalConfiguration
• Configuration keys are Minecraft entity type ids (e.g. minecraft:arrow, minecraft:snowball)
• Unconfigured types keep vanilla behavior; setting a value to 0 removes random spread for that projectile type
• Per-entry default preserves the vanilla uncertainty for that call site

Configuration is applied at the call sites where uncertainty is originally passed (bow/crossbow shootProjectile, throwable items, mob ranged attacks, dispensers, and Bukkit API launch paths), not inside Projectile#shoot or the shared spawn helpers.

Configuration example

projectiles:
  uncertainty:
    minecraft:arrow: 0
    minecraft:snowball: 0
    minecraft:trident: default