[refactor,#59][s]: move packages/portal => examples/catalog as per plan in #59.

What is currently packages/portal is example of a running portal and should move to examples (it will get replaced by an actual portal lib soon).

examples/catalog/components/_shared/CustomLink.tsx

@@ -0,0 +1,15 @@
+type LinkProps = {
+  url: string;
+  format: any;
+};
+
+const CustomLink: React.FC<LinkProps> = ({ url, format }: LinkProps) => (
+  <a
+    href={url}
+    className="bg-white hover:bg-gray-200 border text-black font-semibold py-2 px-4 rounded"
+  >
+    {format}
+  </a>
+);
+
+export default CustomLink;