[FR]: Core - Characteristics - Add endpoint for serving traefik error pages

### Software SNH - Infra - * ### Describe what you'd like to see We should provide an (optional) endpoint in Characteristics to serve a better error page in Traefik when service(s) aren't up yet. ### Is your feature request related to a problem? _No response_ ### Describe alternatives you've considered None ### Additional context Should include: - [ ] characteristics service - [ ] Basic error message - [ ] link back to homepage - [ ] (maybe) healthcheck-based redirect when destination back up - [ ] Traefik- use this page