refactor: update sidebar component to use ViewComponent and improve layout structure

Webzine.WebApplication/Components/Sidebar/Default.cs

@@ -0,0 +1,21 @@
+using Microsoft.AspNetCore.Mvc;
+using Webzine.Repository.Contracts;
+
+namespace Webzine.Components
+{
+    public class SidebarViewComponent : ViewComponent
+    {
+        private readonly IStyleRepository styleRepository;
+
+        public SidebarViewComponent(IStyleRepository styleRepository)
+        {
+            this.styleRepository = styleRepository;
+        }
+
+        public IViewComponentResult Invoke()
+        {
+            var styles = this.styleRepository.FindAll();
+            return this.View(styles);
+        }
+    }
+}