Adds comprehensive Settings page with multiple configuration tabs

Introduces a new Settings page with configurable modules:
- General company information
- Calendar and booking settings
- Billing and payment configurations
- Tracking and analytics integrations

Implements modular ViewComponents for each settings section
Enhances user experience with toggle switches and detailed configuration options

PlanTempus.Application/Features/Settings/Pages/Index.cshtml.cs

@@ -0,0 +1,10 @@
+using Microsoft.AspNetCore.Mvc.RazorPages;
+
+namespace PlanTempus.Application.Features.Settings.Pages;
+
+public class IndexModel : PageModel
+{
+    public void OnGet()
+    {
+    }
+}