fix: Use built-in RNG (#1599)

### Summary

.NET 8 supports Xoroshiro 256** off the shelf and added Shuffle. Switching to that implementation.

### Developer Notes

* Removed many convenience methods that weren't used.

Projects/Server/World/World.cs

@@ -413,7 +413,7 @@ public static class World
         }
         else
         {
-            logger.Warning($"Attempted to call World.AddEntity with '{entity.GetType()}'. Must be a mobile or item.");
+            logger.Warning("Attempted to call World.AddEntity with '{Entity}'. Must be a mobile or item.", entity.GetType());
         }
     }