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.Client/Administration/UI/ManageSolutions/EditSolutionsEui.cs

@@ -0,0 +1,43 @@
+using Content.Client.Eui;
+using Content.Shared.Administration;
+using Content.Shared.Eui;
+using JetBrains.Annotations;
+
+namespace Content.Client.Administration.UI.ManageSolutions
+{
+    /// <summary>
+    ///     Admin Eui for displaying and editing the reagents in a solution.
+    /// </summary>
+    [UsedImplicitly]
+    public sealed class EditSolutionsEui : BaseEui
+    {
+        private readonly EditSolutionsWindow _window;
+
+        public EditSolutionsEui()
+        {
+            _window = new EditSolutionsWindow();
+            _window.OnClose += () => SendMessage(new EditSolutionsEuiMsg.Close());
+        }
+
+        public override void Opened()
+        {
+            base.Opened();
+            _window.OpenCentered();
+        }
+
+        public override void Closed()
+        {
+            base.Closed();
+            _window.OnClose -= () => SendMessage(new EditSolutionsEuiMsg.Close());
+            _window.Close();
+        }
+
+        public override void HandleState(EuiStateBase baseState)
+        {
+            var state = (EditSolutionsEuiState) baseState;
+            _window.SetTargetEntity(state.Target);
+            _window.UpdateSolutions(state.Solutions);
+            _window.UpdateReagents();
+        }
+    }
+}