Create Backstage Simulacrum Demo

[taras]

Motivation

We have several conversations that will require a demo of Simulacrum. Backstage is a very good candidate for demoing Simulacrum because Backstage is an integration platform that connects to many external services. Creating a hermetic development environment for Backstage will make it easier for portal developers to build and maintain their Backstage dev portals.

Approach

This demo will require a bunch of changes.

1. [x] Create a new Backstage instance in examples directory - @wKich
2. [x] Configure app-config.yaml to include configurations for auth0 simulator - @wKich
3. [x] Configure frontend to use auth0 authentication provider - @wKich
4. [x] Add cypress test with auth0 simulation - @wKich
5. [ ] Add graphgen to Simulacrum data store - @cowboyd
6. [ ] Add LDAP simulator plugin - @dagda1
7. [ ] Configure Backstage LDAP processor to use LDAP simulator - @dagda1 @wKich
8. [ ] Configure Backstage to display users that were injected from LDAP - @wKich
9. [ ] ~Add GraphQL API simulator plugin~