[catalog] Make unprocessed entities visible

Create an API route to fetch failed and pending entities, as well as a frontend plugin to view them.

Added a broken entity to the sample data.

Signed-off-by: Rickard Dybeck <dybeck@spotify.com>

packages/backend-next/package.json

@@ -29,6 +29,7 @@
     "@backstage/plugin-app-backend": "workspace:^",
     "@backstage/plugin-auth-node": "workspace:^",
     "@backstage/plugin-catalog-backend": "workspace:^",
+    "@backstage/plugin-catalog-backend-module-unprocessed": "workspace:^",
     "@backstage/plugin-kubernetes-backend": "workspace:^",
     "@backstage/plugin-permission-backend": "workspace:^",
     "@backstage/plugin-permission-common": "workspace:^",