feat(medusa): allow category list api to be filtered by handle (#3825)

what:

- Introduce a filter to the list endpoint to query by handle

why:

- Storefronts mostly interact through handles and not IDs for readability and seo purposes - Take an example of a url `site.com/category/mens-wear`

RESOLVES CORE-1325

.changeset/little-panthers-tell.md

@@ -0,0 +1,5 @@
+---
+"@medusajs/medusa": patch
+---
+
+feat(medusa): allow category api to be filtered by handle