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/Engines/Pathing/FastAStarAlgorithm.cs

@@ -295,8 +295,7 @@ namespace Server.PathAlgorithms.FastAStar
                 int y;
                 switch (i)
                 {
-                    default:
-                    case 0:
+                    default: // 0
                         x = 0;
                         y = -1;
                         break;