Split up the functions to seperate files like the rest of the repo

functions/private/Initialize-InstallAppArea.ps1

@@ -0,0 +1,36 @@
+    function Initialize-InstallAppArea {
+        <#
+            .SYNOPSIS
+                Creates a [Windows.Controls.ScrollViewer] containing a [Windows.Controls.ItemsControl] which is setup to use Virtualization to only load the visible elements for performance reasons.
+                This is used as the parent object for all category and app entries on the install tab 
+                Used to as part of the Install Tab UI generation
+            
+            .PARAMETER TargetElement
+                The element to which the AppArea shoud be added 
+
+        #>
+        param($TargetElement)
+        $scrollViewer = New-Object Windows.Controls.ScrollViewer
+        $scrollViewer.VerticalScrollBarVisibility = 'Auto'
+        $scrollViewer.HorizontalAlignment = 'Stretch'
+        $scrollViewer.VerticalAlignment = 'Stretch'
+        $scrollViewer.CanContentScroll = $true
+
+        $itemsControl = New-Object Windows.Controls.ItemsControl
+        $itemsControl.HorizontalAlignment = 'Stretch'
+        $itemsControl.VerticalAlignment = 'Stretch'
+
+        $itemsPanelTemplate = New-Object Windows.Controls.ItemsPanelTemplate
+        $factory = New-Object Windows.FrameworkElementFactory ([Windows.Controls.VirtualizingStackPanel])
+        $itemsPanelTemplate.VisualTree = $factory
+        $itemsControl.ItemsPanel = $itemsPanelTemplate
+
+        $itemsControl.SetValue([Windows.Controls.VirtualizingStackPanel]::IsVirtualizingProperty, $true)
+        $itemsControl.SetValue([Windows.Controls.VirtualizingStackPanel]::VirtualizationModeProperty, [Windows.Controls.VirtualizationMode]::Recycling)
+
+        $scrollViewer.Content = $itemsControl
+
+        [Windows.Controls.DockPanel]::SetDock($scrollViewer, [Windows.Controls.Dock]::Bottom)
+        $null = $TargetElement.Children.Add($scrollViewer)
+        return $itemsControl
+    }