Add support for 3rd Party Plugins to show in the resources made

**Is your feature request related to a problem? Please describe.**
In the backend resources page where it lists categories added to the project, it would be nice to at least acknowledge other 3rd party plugins used outside of the 1st party plugins.

**Describe the solution you'd like**

- At least list all the resources/categories used in the project, whether they are 1st party or 3rd party.

- List resources created by 3rd party plugins

- Provide a way for 3rd party plugins can create their own pages in the amplify console for resources.

**Additional context**
This is addition to this feature release: https://medium.com/@dabit3/amplify-console-and-cli-now-work-together-five-new-features-6a6ee1d45b1c

The issue names the backend resources page and Amplify console as entry points, but mentions no files or tests. Start by mapping how first-party resources and categories are listed, then define how third-party plugins would register resources and pages; done requires listing all resources and supporting plugin-created resource pages.

Written by the indexing model from the issue text.