fix(core): Optimizes strings / .NET 5 compatibility changes (#354)

- [X] Removes some string allocations (e.g. split)
- [X] Optimizes some collections
- [X] Converts insensitive to extension methods of built-ins.
- [X] Adds ordinal (case sensitive) string helpers
- [X] Fixes conditionals for in-game commands so they use Ordinal comparisons.
- [X] Replaces ToLower.Contains with InsensitiveContains
- [X] Adds ValueStringBuilder
- [X] Implements ValueStringBuilder in a few places where it makes sense
- [X] Removes the redundant Wrap function and replaces it with an optimized version
- [X] Fixes list conversions in Utility

Closes #351

Bumps release version

Projects/UOContent/Items/Books/BaseBook.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Text;
+using Server.Buffers;
 using Server.ContextMenus;
 using Server.Gumps;
 using Server.Multis;
@@ -119,7 +120,7 @@ namespace Server.Items
         {
             get
             {
-                var sb = new StringBuilder();
+                using var sb = new ValueStringBuilder(stackalloc char[256]);
 
                 foreach (var bpi in Pages)
                 {