Add UI for setting solution transfer amount (#4074)

* basic eui and window

* finish EUI, update defaults

* unnecessary usings

* convert to bounduserinterface

* merge me up

merge me up inside

* Fix repeated define for component in prototype

* impl swept UI suggestion

* apply discord reviews

* small changes

Content.Client/Chemistry/UI/TransferAmountBoundUserInterface.cs

@@ -0,0 +1,35 @@
+using Content.Shared.Chemistry;
+using Content.Shared.Chemistry.Reagent;
+using JetBrains.Annotations;
+using Robust.Client.GameObjects;
+using Robust.Shared.GameObjects;
+
+namespace Content.Client.Chemistry.UI
+{
+    [UsedImplicitly]
+    public class TransferAmountBoundUserInterface : BoundUserInterface
+    {
+        private TransferAmountWindow? _window;
+
+        protected override void Open()
+        {
+            base.Open();
+            _window = new TransferAmountWindow();
+
+            _window.applyButton.OnPressed += _ =>
+            {
+                if (int.TryParse(_window.amountLineEdit.Text, out var i))
+                {
+                    SendMessage(new TransferAmountSetValueMessage(ReagentUnit.New(i)));
+                    _window.Close();
+                }
+            };
+
+            _window.OpenCentered();
+        }
+
+        public TransferAmountBoundUserInterface(ClientUserInterfaceComponent owner, object uiKey) : base(owner, uiKey)
+        {
+        }
+    }
+}