feat(frontend): ✨ Add loading component for blog articles (#197)

frontend/src/app/blog/[articleSlug]/loading.tsx

@@ -0,0 +1,15 @@
+import { Skeleton } from "@/components/ui/skeleton";
+import React from "react";
+
+export default function Loading() {
+    return (
+        <div className="m-5 flex h-full w-full items-center justify-center">
+            <div className="flex w-4/5 flex-col items-center justify-center gap-4 bg-background p-5">
+                <Skeleton className="h-16 w-full" />
+                <Skeleton className="h-8 w-full" />
+                <Skeleton className="h-96 w-full" />
+                <Skeleton className="h-96 w-1/2" />
+            </div>
+        </div>
+    );
+}