Fix & extend add reagent verb (#4954)

* AddReagentWindow

* addReagent command

* functional UI

* fix networking

* add comments & docstrings

* Remove unecesary system

* cleanup & close-eui

* tweak default window size

* fix EUI closing error

* fix merge issues

* fix merge

Content.Server/Administration/UI/EditSolutionsEui.cs

@@ -0,0 +1,54 @@
+using Content.Server.Chemistry.Components.SolutionManager;
+using Content.Server.EUI;
+using Content.Shared.Administration;
+using Content.Shared.Eui;
+using JetBrains.Annotations;
+using Robust.Shared.GameObjects;
+using Robust.Shared.IoC;
+
+namespace Content.Server.Administration.UI
+{
+    /// <summary>
+    ///     Admin Eui for displaying and editing the reagents in a solution.
+    /// </summary>
+    [UsedImplicitly]
+    public sealed class EditSolutionsEui : BaseEui
+    {
+        [Dependency] private readonly IEntityManager _entityManager = default!;
+        public readonly EntityUid Target;
+
+        public EditSolutionsEui(EntityUid entity)
+        {
+            IoCManager.InjectDependencies(this);
+            Target = entity;
+        }
+
+        public override void Opened()
+        {
+            base.Opened();
+            StateDirty();
+        }
+
+        public override void Closed()
+        {
+            base.Closed();
+            EntitySystem.Get<AdminVerbSystem>().OnEditSolutionsEuiClosed(Player);
+        }
+
+        public override EuiStateBase GetNewState()
+        {
+            var solutions = _entityManager.GetComponentOrNull<SolutionContainerManagerComponent>(Target)?.Solutions;
+            return new EditSolutionsEuiState(Target, solutions);
+        }
+
+        public override void HandleMessage(EuiMessageBase msg)
+        {
+            switch (msg)
+            {
+                case EditSolutionsEuiMsg.Close:
+                    Close();
+                    break;
+            }
+        }
+    }
+}