Add Letsencrypt supported configuration options for traefik

[IvanChepurnyi]

I am currently using a lot warden on Hetzner as a remote dev environment, and it is quite neat; I can also directly share current progress with my customers without additional deployments.

Right now, I am managing all certificates manually by overriding ones stored in Warden, but it would be great to make it configurable directly in Traefik, as it supports such scenarios:
https://doc.traefik.io/traefik/https/acme/

Also it would be great to remove all hardcoded base domain names and move them into the custom env variable with default to warden.test. If you need help with implementing it, I am open to land a hand.