Overhaul DelayedEffect to support application to multiple targets

Fix DelayedEffect being unusable by monsters due to monsters calling Single Target Apply in their Attack, which DelayedEffect doesn't override, by making Apply (single target) call Apply (multiple targets) which THEN calls the protected Apply function.
Nerf Amanitin to require two injections to be lethal. First injection only stops oxygen from regenerating and slightly saps HP.
Add Cause of Death to Health HUD

Barotrauma/BarotraumaShared/Source/Characters/StatusEffect.cs

@@ -190,7 +190,7 @@ namespace Barotrauma
             }
         }
 
-        private bool HasRequiredItems(Entity entity)
+        public virtual bool HasRequiredItems(Entity entity)
         {
             if (requiredItems == null) return true;
             foreach (RelatedItem requiredItem in requiredItems)
@@ -218,7 +218,7 @@ namespace Barotrauma
             List<ISerializableEntity> targets = new List<ISerializableEntity>();
             targets.Add(target);
 
-            Apply(deltaTime, entity, targets);
+            Apply(type, deltaTime, entity, targets);
         }
 
         public virtual void Apply(ActionType type, float deltaTime, Entity entity, List<ISerializableEntity> targets)
@@ -359,10 +359,7 @@ namespace Barotrauma
 
         public static void UpdateAll(float deltaTime)
         {
-            for (int i = DelayedEffect.List.Count-1; i>= 0; i--)
-            {
-                DelayedEffect.List[i].Update(deltaTime);
-            }
+            DelayedEffect.Update(deltaTime);
         }
 
         public static void StopAll()