Puddles & spreader refactor (#15191)

Content.Client/UserInterface/Controls/SplitBar.xaml

@@ -0,0 +1,7 @@
+<controls:SplitBar xmlns="https://spacestation14.io"
+                      xmlns:controls="clr-namespace:Content.Client.UserInterface.Controls"
+                      MouseFilter="Stop"
+                      Orientation="Horizontal"
+                      HorizontalExpand="True"
+                      MinSize="0 30">
+</controls:SplitBar>

Content.Client/UserInterface/Controls/SplitBar.xaml.cs

@@ -0,0 +1,39 @@
+using Robust.Client.AutoGenerated;
+using Robust.Client.Graphics;
+using Robust.Client.UserInterface.Controls;
+using Robust.Client.UserInterface.XAML;
+
+namespace Content.Client.UserInterface.Controls
+{
+    [GenerateTypedNameReferences]
+    public partial class SplitBar : BoxContainer
+    {
+        public SplitBar()
+        {
+            RobustXamlLoader.Load(this);
+        }
+
+        public void Clear()
+        {
+            DisposeAllChildren();
+        }
+
+        public void AddEntry(float amount, Color color, string? tooltip = null)
+        {
+            AddChild(new PanelContainer
+            {
+                ToolTip = tooltip,
+                HorizontalExpand = true,
+                SizeFlagsStretchRatio = amount,
+                MouseFilter = MouseFilterMode.Stop,
+                PanelOverride = new StyleBoxFlat
+                {
+                    BackgroundColor = color,
+                    PaddingLeft = 2f,
+                    PaddingRight = 2f,
+                },
+                MinSize = new Vector2(24, 0)
+            });
+        }
+    }
+}