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/Multis/BaseHouse.cs

@@ -1688,8 +1688,7 @@ namespace Server.Multis
                     4 => new GenericHouseDoor(facing, 0x6B5, 0xEA, 0xF1),
                     5 => new GenericHouseDoor(facing, 0x6C5, 0xEC, 0xF3),
                     6 => new GenericHouseDoor(facing, 0x6D5, 0xEA, 0xF1),
-                    7 => new GenericHouseDoor(facing, 0x6E5, 0xEA, 0xF1),
-                    _ => null
+                    _ => new GenericHouseDoor(facing, 0x6E5, 0xEA, 0xF1) // 7
                 };
             }
             else if (itemID >= 0x314 && itemID < 0x364)
@@ -1792,8 +1791,7 @@ namespace Server.Multis
                 door = type switch
                 {
                     0 => new GenericHouseDoor(facing, 0x367B, 0xED, 0xF4),
-                    1 => new GenericHouseDoor(facing, 0x368B, 0xEC, 0x3E7),
-                    _ => null
+                    _ => new GenericHouseDoor(facing, 0x368B, 0xEC, 0x3E7) // 1
                 };
             }
             else if (itemID >= 0x409B && itemID < 0x40A3)

Projects/UOContent/Multis/Boats/Strandedness.cs

@@ -1,6 +1,6 @@
 namespace Server.Misc
 {
-    public class Strandedness
+    public static class Strandedness
     {
         private static readonly Point2D[] m_Felucca =
         {

Projects/UOContent/Multis/DynamicDecay.cs

@@ -3,7 +3,7 @@ using System.Collections.Generic;
 
 namespace Server.Multis
 {
-    public class DynamicDecay
+    public static class DynamicDecay
     {
         private static readonly Dictionary<DecayLevel, DecayStageInfo> m_Stages;
 

Projects/UOContent/Multis/HousePlacement.cs

@@ -18,7 +18,7 @@ namespace Server.Multis
         BadRegionRaffle
     }
 
-    public class HousePlacement
+    public static class HousePlacement
     {
         private const int YardSize = 5;