organize theme components into folders

Oqtane.Client/Themes/OqtaneTheme/Layouts/MultiPane.razor

@@ -0,0 +1,20 @@
+@namespace Oqtane.Themes.OqtaneTheme
+@inherits LayoutBase
+
+<div class="row px-4">
+    <Pane Name="Top" />
+</div>
+<div class="row px-4">
+    <div class="col-sm"><Pane Name="Left" /></div>
+    <div class="col-sm"><Pane Name="Content" /></div>
+    <div class="col-sm"><Pane Name="Right" /></div>
+</div>
+<div class="row px-4">
+    <Pane Name="Bottom" />
+</div>
+
+@code {
+    public override string Name => "Multiple Panes";
+
+    public override string Panes => "Top,Left,Content,Right,Bottom";
+}