chore(content): Cleans up abilities and some spell timers (#427)

- [X] Exposes Index/Count on the timer.
- [X] Cleans up abilities
- [X] Combines some spell context/info objects with their timers to reduce allocations
- [X] Fixes a bug where immolating weapon both finishes effect or stops in the wrong order due to a race condition.

Projects/UOContent/Items/Weapons/Abilities/Dismount.cs

@@ -34,7 +34,7 @@ namespace Server.Items
 
         public override void OnHit(Mobile attacker, Mobile defender, int damage)
         {
-            if (!Validate(attacker))
+            if (!Validate(attacker) || !CheckMana(attacker, true))
             {
                 return;
             }
@@ -60,11 +60,6 @@ namespace Server.Items
                 return;
             }
 
-            if (!CheckMana(attacker, true))
-            {
-                return;
-            }
-
             if (Core.ML && attacker is LesserHiryu && Utility.RandomDouble() <= 0.8)
             {
                 return; // Lesser Hiryu have an 80% chance of missing this attack