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/Completions/AddContainer.cs

@@ -0,0 +1,30 @@
+#nullable enable
+using System.Threading.Tasks;
+using Content.Server.GameObjects.Components.Construction;
+using Content.Shared.Construction;
+using JetBrains.Annotations;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Serialization;
+
+namespace Content.Server.Construction.Completions
+{
+    [UsedImplicitly]
+    public class AddContainer : IGraphAction
+    {
+        public void ExposeData(ObjectSerializer serializer)
+        {
+            serializer.DataField(this, x => x.Container, "container", null);
+        }
+
+        public string? Container { get; private set; } = null;
+
+        public async Task PerformAction(IEntity entity, IEntity? user)
+        {
+            if (entity.Deleted || string.IsNullOrEmpty(Container))
+                return;
+
+            var construction = entity.GetComponent<ConstructionComponent>();
+            construction.AddContainer(Container);
+        }
+    }
+}