[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/index.ts

@@ -0,0 +1,5 @@
+import Table from './Table';
+import ErrorMessage from './Error';
+import CustomLink from './CustomLink';
+
+export { Table, ErrorMessage, CustomLink };