Add backpack bombing (#1156)

* Change exploding storages to explode their contents as well

* Change storages to only trigger content explosions when the severity is heavy or destruction

* Make inventories explode their contents as well

* Change InventoryComponent IExAct into an explicit implementation

* Change chain explosions to only trigger for explosion severities larger than or equal to heavy

Content.Server/GameObjects/EntitySystems/ActSystem.cs

@@ -102,8 +102,8 @@ namespace Content.Server.GameObjects.EntitySystems
     }
     public enum ExplosionSeverity
     {
-        Destruction,
-        Heavy,
         Light,
+        Heavy,
+        Destruction,
     }
 }