Implements BattleRandom class with support for Effect Chance, and script hooks to modify this.

src/Battling/ScriptHandling/Script.hpp

@@ -46,6 +46,9 @@ namespace CreatureLib::Battling {
         virtual void OnAfterHits(const ExecutingAttack* attack, Creature* target){};
 
         virtual void PreventSelfSwitch(const SwitchTurnChoice* choice, bool* outResult){};
+
+        virtual void ModifyEffectChance(const ExecutingAttack* attack, Creature* target, float* chance){};
+        virtual void ModifyIncomingEffectChance(const ExecutingAttack* attack, Creature* target, float* chance){};
     };
 }