Upgradeable machines. (#2675)

* Start work on upgradeable machines.

* Upgradeable machines work

* Component requirements for upgradeable machines

* Better container handling

* Remember to not push submodule updates in your PRs, kids!

* Refresh parts after building a machine.

* NetSync false

* Address some reviews, fix some bugs

* Nullable stackhelpers dependencies

* Use container helper method to delete all entities in containers

* Nullable string in AddContainer

* Better examine for machine frame and construction in general

* Machine breakage

* Nullable node

* nullable GraphPrototype

* Re-save saltern for autolathe parts

* Fix SaveLoadSave

Content.Server/Construction/Conditions/ContainerEmpty.cs

@@ -29,13 +29,17 @@ namespace Content.Server.Construction.Conditions
             return container.ContainedEntities.Count == 0;
         }
 
-        public void DoExamine(IEntity entity, FormattedMessage message, bool inDetailsRange)
+        public bool DoExamine(IEntity entity, FormattedMessage message, bool inDetailsRange)
         {
             if (!entity.TryGetComponent(out ContainerManagerComponent? containerManager) ||
-                !containerManager.TryGetContainer(Container, out var container)) return;
+                !containerManager.TryGetContainer(Container, out var container)) return false;
+
+            if (container.ContainedEntities.Count == 0)
+                return false;
+
+            message.AddMarkup(Text);
+            return true;
 
-            if (container.ContainedEntities.Count != 0)
-                message.AddMarkup(Text);
         }
     }
 }