refactor(configmanager): rename UI project and split test projects

Rename ConfigManager to ConfigManager.Ui to match the Core/CLI/UI project
structure, and split the monolithic test project into Core.Tests,
Cli.Tests, and Ui.Tests to align with the source project organization.

NEW/src/Utils/JdeScoping.ConfigManager.Ui/Views/Forms/ConnectionStringsFormView.axaml.cs

@@ -0,0 +1,14 @@
+using Avalonia.Controls;
+
+namespace JdeScoping.ConfigManager.Ui.Views.Forms;
+
+public partial class ConnectionStringsFormView : UserControl
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="ConnectionStringsFormView"/> class.
+    /// </summary>
+    public ConnectionStringsFormView()
+    {
+        InitializeComponent();
+    }
+}