Replacing Networking (#271)

- [X] Removing Kestrel & Libuv
- [X] Cleaning up NetState
- [X] Removing System.IO.Pipelines
- [X] Cleaning up packet reading
- [X] Adds a maximum of 5000 sockets (configurable) to prevent OOM
- [X] Replaces the AsyncState with a thread-safe wrapped boolean called NetworkState
- [X] Removes Parallel.ForEach (no perf gain)
- [X] Removes custom houses compression on another thread
- [X] Test high load scenarios

Bumps release version

Projects/UOContent/Items/Addons/BaseAddonContainer.cs

@@ -295,7 +295,12 @@ namespace Server.Items
                 {
                     var door = doors[i];
 
-                    if (door?.Open == true)
+                    if (door == null)
+                    {
+                        continue;
+                    }
+
+                    if (door.Open)
                     {
                         return AddonFitResult.DoorsNotClosed;
                     }