Update memory management and collection structures

Added `AllocationHandler` struct for memory allocation management.
Added `UnsafeArrayPool` class for pooling `UnsafeArray<T>` instances.
Added new `External` option to `Allocator` enum.
Added default constructors for `UnsafeList`, `UnsafeQueue`, and `UnsafeStack` using `Persistent` allocator.
Changed namespace in `AllocationManager` to `Misaki.HighPerformance.Unsafe.Buffer`.
Changed `MemoryLeakException` to use `MemoryLeakExceptionInfo` for better debugging.
Changed constructor behavior in `UnsafeArray` to clarify memory management responsibilities.
Changed `MemoryUtilities` to include null checks in `Free` and `AlignedFree` methods.
Removed unused using directive in `CollectionBenchmark.cs`.
Removed initialization of `AllocationManager` in `Program.cs`.

Misaki.HighPerformance.Test/Program.cs

@@ -1,9 +1,10 @@
 using Misaki.HighPerformance.Unsafe.Collections;
-using Misaki.HighPerformance.Unsafe.Services;
+using Misaki.HighPerformance.Unsafe.Helpers;
+using System.Numerics;
 
-AllocationManager.Initialize(100);
-
-var unfreeArray = new UnsafeArray<int>(10, Allocator.Persistent);
-var unfreeList = new UnsafeList<int>(10, Allocator.Persistent);
-//unfreeArray.Dispose();
-AllocationManager.Dispose();
+unsafe
+{
+    Console.WriteLine(sizeof(UnsafeHashMap<int, float>));
+    Console.WriteLine(MemoryUtilities.AlignOf<UnsafeHashMap<int, float>>());
+    Console.WriteLine(1 << Math.Min(3, BitOperations.TrailingZeroCount(sizeof(UnsafeHashMap<int, float>))));
+}