Cleanup & Fixes for .NET 5 (#309)

- [X] Fixes several bugs
- [X] Updates more ordinal issues
- [X] Cleans up the code a bit
- [X] Turns classes static that should have been
- [X] Changes TcpServer.Instances to a HashSet

Bumps release version

Projects/UOContent/Misc/ShrinkTable.cs

@@ -3,7 +3,7 @@ using System.IO;
 
 namespace Server
 {
-    public class ShrinkTable
+    public static class ShrinkTable
     {
         public const int DefaultItemID = 0x1870; // Yellow virtue stone
 
@@ -56,7 +56,7 @@ namespace Server
             {
                 line = line.Trim();
 
-                if (line.Length == 0 || line.StartsWith("#"))
+                if (line.Length == 0 || line.StartsWith("#", StringComparison.Ordinal))
                 {
                     continue;
                 }