fix: Adds ReadType/Write(Type) and improves type referencing (#1172)

## Changes
* Improves type hashing by introducing xxHash3 (64bit)
* Removes individual `tdb` files in favor of a single `SerializedTypes.db` file. This file is only used to identify a type that is being deserialized, which doesn't exist.
* Adds duplicate type alias detection
* Adds `AssemblyHandler.FindTypeByHash`

View changed files whitespaces: https://github.com/modernuo/ModernUO/pull/1172/files?diff=split&w=1

## SerializedTypes.db
The serialized types file is used to get back the original name of a type in case it no longer exists in code. This can easily be necessary if a class is renamed in code and no `TypeAlias` is provided.

### Format
byte[4] - version
byte[4] - count
--array--
byte[8] - xxHash
byte[1] - flag, 0 - null, 1 - not null
byte[n] - Full class name in UTF8

### Example
<img width="472" alt="SerializedTypes_Example" src="https://user-images.githubusercontent.com/3953314/195255429-31d24293-6bd1-419e-811b-07874dd0f78d.png">

## Benchmarks
Serialized 500 Type fields. The 8192bytes comes from the _ConcurrentQueue_ that would later be used for SerializedTypes.
Note that the queue is never cleared, so it's size grew considerably.
```cs
|               Method |     Mean |    Error |   StdDev | Allocated |
|--------------------- |---------:|---------:|---------:|----------:|
|      BenchmarkXXHash | 18.44 us | 0.278 us | 0.260 us |    8192 B |
| BenchmarkTypeStrings | 25.09 us | 0.292 us | 0.259 us |         - |
```

TODO:
* Add support in the Serialization Generator for `ReadType()` and `Write(Type)`
* Remove `SetTypeRef` from Serialization Generator

Projects/Server/Utilities/HashUtility.cs

@@ -0,0 +1,48 @@
+/*************************************************************************
+ * ModernUO                                                              *
+ * Copyright 2019-2022 - ModernUO Development Team                       *
+ * Email: hi@modernuo.com                                                *
+ * File: HashUtility.cs                                                  *
+ *                                                                       *
+ * This program is free software: you can redistribute it and/or modify  *
+ * it under the terms of the GNU General Public License as published by  *
+ * the Free Software Foundation, either version 3 of the License, or     *
+ * (at your option) any later version.                                   *
+ *                                                                       *
+ * You should have received a copy of the GNU General Public License     *
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>. *
+ *************************************************************************/
+
+using System;
+using System.Runtime.CompilerServices;
+using Standart.Hash.xxHash;
+
+namespace Server;
+
+/// <summary>
+/// Represents supported non-cryptographic fast hash algorithms.
+/// </summary>
+public enum FastHashAlgorithm
+{
+    None, // Used for collisions where full-data is serialized instead
+    XXHash3_64, // xxHash3 64bit
+}
+
+public static class HashUtility
+{
+    // *************** DO NOT CHANGE THIS NUMBER ****************
+    // * Computed hashes might be serialized against this seed! *
+    // **********************************************************
+    private const ulong xxHash3Seed = 9609125370673258709ul; // Randomly generated 64-bit prime number
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static ulong ComputeHash64(string? data, FastHashAlgorithm algorithm = FastHashAlgorithm.XXHash3_64) =>
+        algorithm switch
+        {
+            FastHashAlgorithm.XXHash3_64 => ComputeXXHash3_64(data),
+            _                            => throw new NotSupportedException($"Hash {algorithm} is not supported.")
+        };
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static ulong ComputeXXHash3_64(string? data) => data == null ? 0 : xxHash3.ComputeHash(data, xxHash3Seed);
+}