fix: Optimizes FindItemsByType by removing allocations. (#1515)

### Summary
Container enumeration is in dire need of optimization. Thanks to @stefanomerotta for initiating this work with PR #1443. This PR handles a small part of what Stefan started. Also included are some bug fixes.

### Method Signatures

```cs
// Use with foreach without moving/deleting items
FindItemsByTypeEnumerator<T> FindItemsByType<T>(bool recurse = true, Predicate<T> predicate = null)

// Use with foreach when moving/deleting items
QueuedItemsEnumerator<T> EnumerateItemsByType<T>(bool recurse = true, Predicate<T> predicate = null)

// Use when iterating multiple times or queuing
PooledRefQueue<T> QueueItemsByType<T>(bool recurse = true, Predicate<T> predicate = null)

// Use when iterating multiples times or manipulating elements without traversing
PooledRefList<T> ListItemsByType<T>(bool recurse = true, Predicate<T> predicate = null)
```

* `FindItemsByType<T>` has changed from returning `List<T>` to `FindItemsByTypeEnumerator<T>` - This method is not safe to use in situations where an item may get consumed, deleted, or moved.

* `EnumerateItemsByType<T>` was added as a safe way to iterate and manipulate items.
  * **Note**: EnumerateItemsByType will _completely traverse the container_ before iteration starts because it uses `QueueItemsByType` under the hood.

* `QueueItemsByType<T>`  and `ListItemsByType<T>` was added to return a queue or list of items to iterate multiple times and manipulate the items. This isn't the most efficient since it uses a predicate and can result in 2 or 3 total iterations unnecessarily.

### Bug Fixes
- [X] Fishing had an error in the random check that may have caused slight bias.

Projects/UOContent/Commands/Generic/Implementors/ContainedCommandImplementor.cs

@@ -67,7 +67,7 @@ namespace Server.Commands.Generic
 
                 var list = new List<object>();
 
-                foreach (var item in cont.FindItemsByType<Item>())
+                foreach (var item in cont.FindItemsByType())
                 {
                     if (ext.IsValid(item))
                     {