Custom 404 page

[r10513]

Is there an existing issue for this?

• [X] I have searched the existing issues

Describe the problem to be solved

First of all thank you for your wonderful package! I would like to use your pages (for instance, the l7-dark template) but with a custom 404 page.

Suggest a solution

Would it be possible to implement an environmental variable, such as CUSTOM_404 that, if not set, has a default to False? Then, in the docker container, is just a matter to set CUSTOM_404 to true and implement the correct mapping via a volume entry.. Something like

  error-pages:
    image: tarampampam/error-pages:latest
    ports:
      - 8080:8080
    volumes:
      - /path/to/local/404.html:/custom/404.html:ro
    environment:
      TEMPLATE_NAME: l7-dark
      CUSTOM_404:  true
    labels:
      traefik.enable: true

Thank you!

Additional context

No response