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/Commands/SkillsMenu.cs

@@ -3,7 +3,7 @@ using Server.Targeting;
 
 namespace Server.Commands
 {
-    public class Skills
+    public static class SkillsMenu
     {
         public static void Initialize()
         {
@@ -15,8 +15,7 @@ namespace Server.Commands
             CommandSystem.Register("Skills", AccessLevel.Counselor, Skills_OnCommand);
         }
 
-        [Usage("Skills")]
-        [Description("Opens a menu where you can view or edit skills of a targeted mobile.")]
+        [Usage("Skills"), Description("Opens a menu where you can view or edit skills of a targeted mobile.")]
         private static void Skills_OnCommand(CommandEventArgs e)
         {
             e.Mobile.Target = new SkillsTarget();