chore: deprecate standalone SecureStoreManager utility

Move SecureStoreManager project and tests to Deprecated folder and remove
from solution. SecureStore functionality is now integrated into ConfigManager.

Deprecated/JdeScoping.SecureStoreManager/ViewModels/AsyncRelayCommand.cs

@@ -0,0 +1,83 @@
+using System.Windows.Input;
+
+namespace JdeScoping.SecureStoreManager.ViewModels;
+
+/// <summary>
+/// An async command implementation that properly handles async operations.
+/// </summary>
+public class AsyncRelayCommand : ICommand
+{
+    private readonly Func<Task> _execute;
+    private readonly Func<bool>? _canExecute;
+    private bool _isExecuting;
+    private EventHandler? _canExecuteChanged;
+
+    /// <summary>
+    /// Raised when the result of CanExecute() may have changed.
+    /// </summary>
+    public event EventHandler? CanExecuteChanged
+    {
+        add => _canExecuteChanged += value;
+        remove => _canExecuteChanged -= value;
+    }
+
+    /// <summary>
+    /// Creates a new AsyncRelayCommand that can always execute.
+    /// </summary>
+    /// <param name="execute">The async action to execute.</param>
+    public AsyncRelayCommand(Func<Task> execute)
+        : this(execute, null)
+    {
+    }
+
+    /// <summary>
+    /// Creates a new AsyncRelayCommand with a CanExecute predicate.
+    /// </summary>
+    /// <param name="execute">The async action to execute.</param>
+    /// <param name="canExecute">The predicate to determine if the command can execute.</param>
+    public AsyncRelayCommand(Func<Task> execute, Func<bool>? canExecute)
+    {
+        _execute = execute ?? throw new ArgumentNullException(nameof(execute));
+        _canExecute = canExecute;
+    }
+
+    /// <summary>
+    /// Determines whether the command can be executed in its current state.
+    /// </summary>
+    /// <param name="parameter">The command parameter (unused).</param>
+    public bool CanExecute(object? parameter)
+    {
+        return !_isExecuting && (_canExecute?.Invoke() ?? true);
+    }
+
+    /// <summary>
+    /// Executes the async command if it can execute.
+    /// </summary>
+    /// <param name="parameter">The command parameter (unused).</param>
+    public async void Execute(object? parameter)
+    {
+        if (!CanExecute(parameter))
+            return;
+
+        _isExecuting = true;
+        RaiseCanExecuteChanged();
+
+        try
+        {
+            await _execute();
+        }
+        finally
+        {
+            _isExecuting = false;
+            RaiseCanExecuteChanged();
+        }
+    }
+
+    /// <summary>
+    /// Raises the CanExecuteChanged event.
+    /// </summary>
+    public void RaiseCanExecuteChanged()
+    {
+        _canExecuteChanged?.Invoke(this, EventArgs.Empty);
+    }
+}